CIS Explained Simply: Understanding Tax Deductions and Payments in the Construction Industry

Ask ten people on a building site what CIS actually is and you will get ten slightly different answers. Some will tell you it is a tax. Others will say it is a registration scheme. A few will insist it is something their accountant deals with once a year. All of them are partly right, which is precisely why so many contractors and subcontractors end up confused, underpaid, overpaid, or on the receiving end of an HMRC penalty notice.

The Construction Industry Scheme is not complicated once you strip away the jargon. At its heart, it is a system where the business paying for construction work holds back a slice of the payment and sends it to HMRC on the worker’s behalf. Everything else, the verification checks, the monthly returns, the payment statements, the deduction rates, exists to make that basic idea work fairly across hundreds of thousands of construction businesses.

This guide is written for anyone who needs CIS explained simply, whether you are a plasterer who has just gone self employed, a main contractor taking on your first subcontractor, or an office manager who has inherited the CIS returns and would rather not get them wrong.

We will walk through who registers, who deducts, how the maths works, what should appear on a payment statement, how deducted tax comes back to you, and where people most often slip up.

One important note before we start. This article is general guidance, not tax advice. CIS interacts with VAT, employment status, and corporation tax in ways that depend heavily on your circumstances. Where money or compliance risk is involved, speak to a qualified accountant or check the current position directly with HMRC.

What Is the Construction Industry Scheme (CIS)?

The Construction Industry Scheme is the HMRC’s set of rules designed to control and manage payment practices between a contractor and subcontractor. When a company contracts another organization to provide construction services, the former pays the latter according to CIS rules.

For this industry, HMRC takes percentage from a payment made to a subcontractor as a deduction. Deductions apply to labour costs and are paid to HMRC by a contractor, not by a subcontractor. The deducted amount is an amount that will be due to the subcontractor’s taxation, including income tax and National Insurance.

It implies that the money owed to a subcontractor reduces an amount of tax he or she has to pay. Additionally, an amount of tax withheld by a contractor can be reclaimed by a subcontractor when he or she completes a tax return or when his or her company pays wages and taxes. A reclaimed amount of tax will thus reduce the tax liability for a subcontractor.

Two roles matter under CIS, and the scheme defines them by what you are doing on a particular job rather than by the size of your business:

• Contractor: a business that pays another business or individual to carry out construction work.
• Subcontractor: a business or individual that carries out construction work for a contractor and gets paid for it.

A great many construction businesses are both at the same time. A bricklaying firm invoicing a main contractor is a subcontractor on that job. The moment it brings in a labourer on a self employed basis, it becomes a contractor too, with all the responsibilities that follow.

What counts as construction work under CIS

HMRC casts the net fairly wide. Construction operations covered by the scheme generally include:

• Preparing a site, including laying foundations and providing access works
• Demolition and dismantling
• Building work of all kinds, permanent or temporary
• Alterations, repairs, extensions and refurbishment
• Installing systems for heating, lighting, power, water, drainage and ventilation
• Civil engineering work such as roads, bridges and pipelines
• Decorating, including painting inside and out
• Cleaning the inside of a building after construction work has been completed

Work that falls outside the scheme

Plenty of activity happens on or around a construction site without being caught by CIS. Common exclusions include:

• Architecture, surveying and consultancy
• Hiring out scaffolding where no labour is supplied
• Carpet fitting
• Delivering materials to site
• Manufacturing or off site fabrication of components, plant or machinery
• Running site facilities such as a canteen, medical room or security office

The boundaries are not always obvious, and mixed contracts cause particular trouble. If a single contract covers both construction and non construction work, HMRC generally expects the whole payment to be treated under CIS. Where you are unsure, get the position confirmed before the first payment rather than after.

Why the CIS Exists

Construction has always been a mobile, project driven industry. Workers move between sites and between employers, work is often short term, and cash has historically played a bigger role than in most sectors. That combination made it unusually easy for income to go unreported, and for tax liabilities to disappear along with a trading name.

HMRC’s answer was to collect tax closer to the source. Rather than trusting that every self employed tradesperson would set money aside and settle up at the end of the year, the scheme places the obligation on the party making the payment. Contractors are generally larger, better resourced, and easier for HMRC to monitor than a sole trader working across four sites in a month.

The scheme also serves a second purpose that is easy to overlook. It creates a documented trail of who paid whom, for what, and when. Verification records, monthly returns and payment statements together give HMRC a picture of activity across the sector, and they give honest businesses evidence that they have done the right thing.

There is a genuine benefit for subcontractors too, even if it rarely feels that way when the deduction lands. Paying tax gradually through the year is easier on cash flow than facing a single large bill in January. Many registered subcontractors with modest turnover and reasonable expenses find they have overpaid across the year and receive a refund.

Who Must Register for CIS?

Contractors

Registration is compulsory for contractors. If you pay subcontractors for construction work, you must register with HMRC as a contractor before you make the first payment. You cannot wait until the end of the month and sort it out retrospectively, because verification has to happen before payment.

Registering as a contractor sets up a CIS scheme alongside your PAYE scheme. From that point you take on a fixed set of duties: verify subcontractors, deduct at the correct rate, file a monthly return, issue payment statements, and pay HMRC on time.

Deemed contractors

Some organisations fall into the scheme even though construction is not their trade. These are known as deemed contractors, and they include large property investors, retailers, manufacturers, housing associations and public bodies that spend heavily on construction.

The test is based on construction spending over a rolling period rather than on what sector you say you are in. Businesses need to monitor their construction expenditure and register once it passes the threshold set by HMRC.

Because the rules here changed in recent years and the monitoring is continuous rather than annual, this is an area where finance teams should check the current HMRC position rather than rely on what was true a few years ago.

Subcontractors

Subcontractor registration works differently. It is not legally compulsory, but choosing not to register is an expensive decision. Unregistered subcontractors have deductions taken at the higher rate, which means a significantly larger slice of every payment sits with HMRC until the tax return is settled.

Registering is straightforward. Sole traders register through their Government Gateway account using their Unique Taxpayer Reference and National Insurance number. Limited companies register using the company UTR and company registration number. Partnerships register the partnership as well as each partner. The process is free and usually takes a matter of days.

Businesses that are both

If you invoice contractors and also pay your own subcontractors, you need to be registered in both capacities. This is extremely common among small and medium sized firms, and it is where record keeping starts to matter. You will have deductions taken from your income and you will be making deductions from other people’s payments, and HMRC expects both sides to be accurate.

Who Pays CIS?

This is the single most common point of confusion, so it is worth being precise. The subcontractor bears the cost of the deduction, because it comes out of money they would otherwise receive. The contractor carries the legal responsibility, because they are the one who must calculate it, withhold it, report it and hand it over.

If a contractor deducts the wrong amount, HMRC pursues the contractor, not the subcontractor. If a contractor fails to deduct at all when they should have, the contractor can be liable for the shortfall out of their own pocket. That asymmetry explains why experienced contractors are so careful about verification.

Here is how the responsibilities divide in practice:

One further point deserves emphasis. CIS applies only to self employed subcontractors. If someone is genuinely an employee, they belong on PAYE with holiday pay, sick pay and employment rights, and putting them through CIS instead does not change that.

Employment status is determined by the reality of the working relationship, not by the label on the invoice, and HMRC takes false self employment in construction seriously.

How CIS Tax Deductions Work

Contractor responsibilities

A contractor’s CIS duties follow a predictable monthly rhythm. The core obligations are:

1. Verify every new subcontractor with HMRC before the first payment is made.
2. Apply the deduction rate HMRC returns for that subcontractor, not the rate the subcontractor claims to have.
3. Deduct only from the labour element, after removing allowable costs such as materials.
4. Issue a payment and deduction statement to each subcontractor for every tax month in which a deduction was made.
5. Submit a monthly CIS return to HMRC listing every subcontractor paid and every deduction made.
6. Pay the deducted amounts to HMRC by the deadline.
7. Keep records that support every figure reported.

The tax month runs from the 6th of one month to the 5th of the next. The monthly return is due by the 19th, and payment deadlines follow closely behind. Missing a return deadline triggers an automatic penalty even where no tax is owed, which catches out plenty of businesses in quiet months.

Subcontractor responsibilities

Subcontractors have fewer formal duties, but the ones they do have are the difference between a smooth refund and a drawn out query. A subcontractor should:

• Register with HMRC under CIS to secure the lower deduction rate
• Give the contractor the correct legal name, UTR and, where relevant, company registration number
• Show labour and materials as separate lines on every invoice
• Charge and account for VAT correctly, including under the domestic reverse charge where it applies
• Collect and file every payment and deduction statement received
• Keep records of expenses so the final tax position is accurate

Notice how much rests on the invoice. A subcontractor who lumps everything into a single figure labelled “works as agreed” is inviting a deduction on the full amount, materials included. That is not the contractor being awkward. Without a stated split, the contractor has no defensible basis for reducing the deduction.

The verification process

Verification is how the contractor finds out which rate to apply. It is done through HMRC’s CIS online service or through commercial payroll software, and it must happen before the first payment to a new subcontractor.

The contractor submits the subcontractor’s details, typically the name, UTR and either the National Insurance number for a sole trader or the company registration number for a limited company. HMRC checks its records and returns two things: the deduction rate to use, and a verification reference number.

Getting the details right matters more than people expect. HMRC matches on exact information. A trading name instead of a legal name, a transposed digit in a UTR, or a company number belonging to a dormant entity will all produce a failed match, and a failed match means the higher rate applies regardless of whether the subcontractor is registered.

Verification does not need repeating for every job. Once a subcontractor has been verified and included on a return, that verification generally remains valid for the current tax year and the two tax years that follow, provided you keep paying them. If there is a long gap, verify again.

Deduction percentages

Verification produces one of three outcomes, and each one determines the rate the contractor must use for that subcontractor:

• Registered and matched: deduct at 20% of the labour element
• Unregistered or not matched to HMRC records: deduct at 30%
• Gross payment status: deduct nothing and pay the invoice in full

The contractor uses the rate HMRC supplies, not the rate the subcontractor believes applies to them. Where the two disagree, it is the subcontractor’s job to sort the position out with HMRC.

Gross payment status

Gross payment status allows a subcontractor to be paid in full, with no CIS deduction, and to settle their tax liability entirely through their normal tax return or corporation tax. For businesses with real payroll and material costs, the cash flow difference is substantial.

It is not automatic. HMRC applies three tests before granting it:

• The business test. You must carry out construction work in the UK, run the business largely through a bank account, and be able to show it is a genuine business.
• The turnover test. Construction turnover, excluding VAT and the cost of materials, must reach a minimum level. HMRC applies a threshold per sole trader, partner or director, with an alternative combined threshold available to larger companies and partnerships.
• The compliance test. Tax returns and payments must have been submitted and made on time over the preceding period, with only limited tolerance for minor lapses.

Gross payment status is reviewed by HMRC on an ongoing basis, and it can be withdrawn if compliance slips. Losing it is disruptive, because deductions start again immediately and contractors will pick up the change at the next verification.

Anyone holding gross status should treat filing deadlines as non negotiable. Note also that the compliance test now takes account of VAT obligations as well as direct taxes, so a pattern of late VAT returns can put the status at risk.

Understanding CIS Deduction Rates

Three rates apply under the scheme, and which one you get depends entirely on your registration and compliance position with HMRC.

The 20% deduction

This is the standard rate and covers the majority of subcontractors in the industry. It applies once the subcontractor has registered under CIS and the contractor has verified them successfully. For most self employed tradespeople with typical expenses, twenty percent of labour income is broadly in the right region, which is why refunds are common but rarely enormous.

The 30% deduction

The higher rate is applied in two situations: the subcontractor has not registered under CIS, or HMRC cannot match the details supplied at verification. The second cause is more common than the first, and it is almost always fixable.

The important thing to understand is that 30% is not a penalty in the technical sense. The extra money is still credited to the subcontractor’s tax account and still comes back if it exceeds the eventual liability. What it does is take cash out of the business for months, which for a small operation can be the difference between comfortable and struggling.

Gross payment status (0%)

With gross status, the contractor pays the invoice in full and reports the payment on the monthly return without a deduction. The subcontractor still owes tax on the profits, but pays it in the normal way through Self Assessment or corporation tax rather than in instalments through the year.

When deductions apply, and what is excluded

CIS deductions are never taken from the whole invoice. Several elements are removed before the percentage is applied:

• VAT. Never subject to CIS deduction under any circumstances.
• Materials. The actual cost the subcontractor paid, not a marked up figure.
• Consumable stores. Items used up in the course of the work, such as sealant, fixings and abrasives.
• Fuel used in plant. Excluded, although fuel for travelling to and from site is not.
• Plant hired from a third party. Excluded where the subcontractor genuinely hired it in. If the subcontractor owns the plant, the charge forms part of the payment subject to deduction.
• The CITB levy. Where it is separately identified.

A word of caution on materials. Contractors are entitled to ask for evidence, and HMRC expects them to make a reasonable judgement rather than accept any figure presented.

A decorator invoicing three days of work with two thousand pounds of materials should expect questions. Inflating the materials line to reduce a deduction is not a grey area, it is a false statement on a tax document.

How Contractors Calculate CIS Payments

The calculation itself is simple arithmetic once the invoice is broken down correctly. The reliable method is to work through it in the same order every time.

1. Start with the gross invoice value, excluding VAT.
2. Subtract the cost of materials and other allowable items.
3. The remaining figure is the labour element, which is the amount subject to deduction.
4. Apply the verified rate to the labour element.
5. Subtract the deduction from the invoice total to arrive at the net payment.
6. Record the gross figure, the materials figure and the deduction for the monthly return and the payment statement.

Worked example one: registered subcontractor at 20%

An electrician registered under CIS invoices a main contractor for a first fix on a small residential development. The invoice separates labour from materials.

Worked example two: the same invoice at 30%

Now assume the same electrician has not registered under CIS, or the verification failed because the UTR supplied did not match HMRC’s records.

The difference is £240 on a single invoice. Across a year of similar work, that is several thousand pounds sitting with HMRC instead of in the business bank account. It comes back eventually, but the cash flow cost in the meantime is real.

Worked example three: gross payment status

Worked example four: what happens without a materials split

This example shows why invoice presentation matters so much. A groundworker submits an invoice for £3,250 with no breakdown, even though £850 of it was spent on aggregate and pipework.

£170 of avoidable cash flow loss on one invoice, purely down to how it was written. Multiply that across a busy year and the case for tidy invoicing makes itself.

A note on VAT and the domestic reverse charge

VAT sits outside the CIS calculation entirely, but the two interact in a way that trips people up. Under the VAT domestic reverse charge for building and construction services, many business to business construction supplies no longer carry VAT on the invoice. Instead the customer accounts for it.

The practical effect is that a reverse charge invoice shows a lower total than people expect, and it is easy to apply the CIS deduction to the wrong figure or to double count VAT. The rule to hold on to is straightforward: CIS is calculated on the labour element excluding VAT, whether the reverse charge applies or not.

The VAT treatment changes who accounts for VAT, not what CIS is calculated on. If your business regularly issues or receives reverse charge invoices, it is worth having your accountant review a sample of both.

What Is a CIS Payment Statement?

A payment and deduction statement is the document a contractor gives a subcontractor confirming what was paid and what was deducted. It is often called a CIS voucher or a CIS statement, and it is the subcontractor’s evidence when they come to reclaim the tax.

Contractors must issue a statement for every tax month in which a deduction was made, within 14 days of the end of that tax month. Statements are not required where the subcontractor holds gross payment status, since nothing has been deducted.

What should appear on the statement

• The contractor’s name and their employer tax reference
• The end date of the tax month the payment falls into, for example 5 October
• The subcontractor’s name
• The subcontractor’s Unique Taxpayer Reference
• The verification reference number, where the higher rate was applied because the subcontractor could not be matched
• The gross amount of the payment, excluding VAT
• The cost of materials that reduced the amount subject to deduction
• The amount of the CIS deduction

Why these statements matter so much

For subcontractors, statements are the paperwork that turns a deduction into a refund. HMRC will generally accept the figures on a tax return without seeing the statements, but if a claim is queried, missing statements make the position difficult to defend.

Limited companies in particular can find repayment claims delayed while HMRC reconciles their figures against contractor returns.

Practical habits that save trouble later:

• Save every statement in a dedicated folder, organised by tax year and contractor
• Check each statement against your own invoice records as it arrives, not in January
• Chase missing statements within the same tax year while the contractor’s records are current
• Keep a simple running total of deductions so you know your position before your accountant tells you

If a contractor refuses to provide statements, ask in writing first. Persistent failure can be reported to HMRC, and contractors face penalties for not issuing them.

How Subcontractors Can Claim Back CIS Tax

Money deducted under CIS is not lost. How you recover it depends entirely on your business structure, and this is where the two routes diverge sharply.

Sole traders and partnerships: Self Assessment

If you are self employed as a sole trader or in a partnership, CIS deductions are reclaimed through your Self Assessment tax return. The process works like this:

1. Record your total business income for the tax year, using the gross figures from your invoices rather than the net amounts you received.
2. Deduct your allowable business expenses to arrive at your taxable profit.
3. Calculate the income tax and National Insurance due on that profit.
4. Enter the total CIS deductions taken during the year in the relevant box on the return.
5. HMRC sets the deductions against your liability. If they exceed it, the balance is repaid.

A frequent error is entering net rather than gross income. If you received £2,770 after a £480 deduction, your income for the return is £3,250, and £480 goes in the CIS deductions box. Entering the net figure and also claiming the deduction understates your income and produces a refund you are not entitled to.

Refunds are usually processed after the end of the tax year on 5 April, once the return has been submitted. Filing early in the new tax year, rather than waiting until the January deadline, is the single most effective way to get your money back sooner.

Limited companies: offsetting through payroll

Limited companies cannot reclaim CIS deductions through the corporation tax return. Instead, deductions suffered are offset against the company’s employer liabilities through the payroll system.

The mechanism is the Employer Payment Summary, submitted to HMRC as part of the RTI payroll process. The company reports the CIS deductions taken from it during the tax month, and HMRC reduces what the company owes in PAYE tax, National Insurance and its own CIS liabilities accordingly.

If deductions suffered exceed the company’s employer liabilities, the surplus carries forward through the tax year. Any amount still unused at the end of the year can be claimed as a repayment or set against other taxes the company owes.

Two points catch companies out repeatedly.

• First, an EPS must actually be submitted for the offset to happen. Recording the deduction in your bookkeeping software does nothing on its own.
• Second, the offset only works against employer liabilities. A company with no payroll has nothing to offset against during the year and must wait until the year end to reclaim.

Structure comparison

For a fuller comparison of how the contractor and subcontractor roles work in practice, including the paperwork each side needs to keep, our companion guide CIS Explained goes into more detail on both perspectives.

Common CIS Mistakes

Most CIS problems are not exotic. They come from the same handful of errors repeating across thousands of businesses.

Failing to verify, or verifying with the wrong details

Paying a new subcontractor before verification is a breach of the rules, and the contractor carries the liability if the wrong rate was applied. Just as common is verifying with a trading name rather than a legal name, or with a slightly wrong UTR, which produces an unnecessary higher rate deduction and an unhappy subcontractor.

Fix: collect legal name, UTR and company number in writing before the first job, and verify the same day.

Applying the wrong deduction rate

Contractors sometimes take a subcontractor’s word for their status, or carry forward a rate from a previous year without rechecking. Rates change, particularly when gross payment status is granted or withdrawn.

Fix: use the rate HMRC returns at verification, and reverify where there has been a long gap in payments.

Deducting from the wrong figure

Applying the percentage to the full invoice including materials, or including VAT in the calculation, are both frequent and both cost the subcontractor money.

Fix: build the calculation into a template that always removes VAT and materials before applying the rate.

Missing or late payment statements

Statements are often the first thing to slip when a contractor is busy. Subcontractors then arrive at the tax return with incomplete records, and reconstructing a year of deductions after the fact is slow and error prone.

Fix: generate statements as part of the same monthly routine as the CIS return, not as a separate task.

Late or missing monthly returns

The monthly return is due even in months where no subcontractors were paid, unless HMRC has been told the scheme is temporarily inactive. Automatic penalties start at a fixed amount for being a single day late and escalate the longer a return remains outstanding.

Fix: set a recurring reminder for the 19th, and notify HMRC of periods of inactivity rather than simply not filing.

Poor record keeping

HMRC expects contractors to keep records of gross payments, materials deducted and CIS withheld, along with evidence supporting the figures. Records must be retained for several years after the tax year they relate to, and inadequate records can attract a penalty in their own right.

Fix: keep digital copies of invoices, verification references, statements and return submissions in one structured location.

Confusing VAT and CIS

Since the introduction of the domestic reverse charge, invoices in the sector look different, and errors have multiplied. Common versions include charging VAT when the reverse charge should apply, applying CIS to a VAT inclusive figure, and treating reverse charge invoices as though they were zero rated.

Fix: have an accountant review your invoice templates once, then apply them consistently.

Misclassifying employees as subcontractors

Putting someone through CIS does not make them self employed. Where a worker is under close supervision, works set hours, uses the contractor’s tools and has no real financial risk, HMRC may well treat them as an employee. The consequences include back PAYE, National Insurance, interest and penalties.

Fix: assess employment status honestly at the outset and document the reasoning.

Related: Essential Qualifications and Certifications for Construction Workers in the UK

Tips for Staying HMRC Compliant

Compliance is easier when it is a routine rather than a scramble. The businesses that never have CIS problems tend to do the same unremarkable things every month.

Monthly compliance checklist for contractors

• Verify all new subcontractors before their first payment
• Check that every invoice separates labour, materials and VAT clearly
• Apply the HMRC verified rate to the labour element only
• Reconcile deductions against payments made during the tax month
• Issue payment and deduction statements within 14 days of the tax month end
• Submit the monthly CIS return by the 19th, including nil returns where relevant
• Pay deductions to HMRC by the relevant deadline for your payment method
• File verification references, statements and return confirmations together

Ongoing checklist for subcontractors

• Confirm your CIS registration is active and your details with HMRC are current
• Give contractors your exact legal name and UTR, not a trading name
• Invoice with a clear labour and materials split every time
• Collect every payment statement and check it against your records
• Track expenses throughout the year rather than reconstructing them in January
• Set aside funds for any balance of tax due beyond what has been deducted
• File your return early in the new tax year to speed up any refund

A note on gross payment status

If you hold gross payment status, your compliance record is under continuous review. Late VAT returns, late corporation tax payments and missed CIS returns can all put it at risk. Treat every filing deadline as a condition of keeping the status, because in practice that is what it is.

Systems and software

Most modern accounting and payroll packages handle CIS verification, deduction calculation, statement generation and return submission in one place.

For a contractor paying more than a handful of subcontractors, the cost of proper software is almost always lower than the cost of a single set of penalties. Spreadsheets work for very small operations, but they depend entirely on the person maintaining them remembering the deadlines.

When to bring in an accountant

There is no shame in getting help, and some situations genuinely warrant it: mixed contracts where CIS status is unclear, businesses acting as both contractor and subcontractor, applications for gross payment status, HMRC compliance checks, reverse charge VAT questions, and any situation where employment status is in doubt. An accountant who specialises in construction will usually pay for themselves in avoided errors.

Also Read: How to Apply for Carpenter CSCS Card

Frequently Asked Questions

Is CIS a separate tax?

No. CIS is a collection mechanism, not a tax in its own right. The money deducted is an advance payment towards the subcontractor’s income tax and National Insurance, and it is credited to their tax account.

Do I have to register as a subcontractor?

Registration is not compulsory, but not registering means a 30% deduction instead of 20%. Since the money is recoverable either way, the practical effect of staying unregistered is simply that more of your cash sits with HMRC for longer.

Can I be a contractor and a subcontractor at the same time?

Yes, and many construction businesses are. You register in both capacities, suffer deductions on your own income, and make deductions from the subcontractors you pay. Both sets of records need to be accurate.

Are CIS deductions taken from materials?

No. Deductions apply only to the labour element. The genuine cost of materials, consumable stores, fuel used in plant and plant hired from a third party are all removed before the percentage is applied. Materials must be shown at cost, not marked up.

What happens if a contractor does not verify me?

Without verification the contractor has no HMRC confirmed rate to apply, and in practice this often results in the higher 30% rate. The contractor is also in breach of the rules and may be liable for any under deduction. Ask for confirmation that verification has been carried out before the first payment.

How long does a CIS refund take?

Timing depends on when you file and whether HMRC has any queries. Sole traders who submit their Self Assessment return promptly after 5 April often see repayment within a few weeks. Limited company claims can take longer, particularly where HMRC needs to reconcile the figures against contractor returns.

Do I need to give payment statements to subcontractors with gross payment status?

No. Since no deduction has been made, there is nothing to certify. You still report the payment on your monthly CIS return.

Does CIS apply to work carried out outside the UK?

The scheme applies to construction operations in the UK and its territorial waters. Work carried out abroad falls outside it, although a business based abroad doing construction work in the UK is generally within the scheme.

What is the difference between CIS and PAYE?

PAYE applies to employees and covers income tax, National Insurance, holiday pay and employment rights. CIS applies to self employed subcontractors and covers only an advance deduction towards their tax. Putting a genuine employee through CIS does not change their employment status, and HMRC can reclassify the relationship.

Do I still need to file a CIS return in a month with no payments?

Yes, unless you have told HMRC the scheme will be inactive for a period. A nil return is required in months where you made no payments to subcontractors, and the same automatic penalties apply for filing it late.

Can CIS deductions be offset against corporation tax?

Not directly. Limited companies offset CIS deductions suffered against their PAYE, National Insurance and CIS liabilities through the Employer Payment Summary. Any balance remaining at the end of the tax year can be repaid or set against other taxes owed, which may include corporation tax by agreement with HMRC.

What records do I need to keep, and for how long?

Contractors should keep records of gross payments, materials deducted, CIS withheld and the evidence supporting each figure, including verification references. HMRC requires these to be retained for several years after the end of the tax year they relate to, and can charge a penalty where records are inadequate. Check the current retention period on GOV.UK, as guidance is updated periodically.

Final Thoughts

Getting CIS explained simply comes down to holding on to one idea: the contractor takes a slice of the labour payment and sends it to HMRC on the subcontractor’s behalf. Verification decides how big the slice is. The invoice split decides what the slice is taken from. Payment statements prove it happened. Self Assessment or the payroll offset gives it back.

For contractors, the priority is process. Verify before you pay, deduct from the right figure, issue statements on time, and file every month without exception. None of these tasks is difficult in isolation. The businesses that get into trouble are almost always the ones that let them pile up, then try to reconstruct a quarter’s worth of records from memory and bank statements.

For subcontractors, the priority is paperwork. Register so you are on the lower rate. Give contractors your exact legal details so verification succeeds first time. Split labour and materials on every invoice. Keep every statement. Track your expenses through the year. Do those five things and your tax position will be accurate, your refund will arrive faster, and you will spend far less time on the phone chasing figures.

The Construction Industry Scheme has a reputation for being awkward, and some of that is deserved, particularly where it meets VAT and employment status. But the core mechanics are consistent, the deadlines are predictable, and the rules reward businesses that are organised. Build the routine once and CIS becomes background admin rather than a recurring problem.

Finally, treat this guide as a starting point rather than the last word. HMRC updates its guidance, thresholds and compliance requirements from time to time, and your own circumstances may raise questions this article cannot answer. For anything involving significant sums, unusual contracts, or a compliance check, check the current position on GOV.UK and speak to a qualified accountant with construction sector experience.

Published by CRECSO UK.