CIS Explained for UK Builders and Tradesmen

The Construction Industry Scheme (CIS) confuses more UK tradesmen than almost any other tax topic. It is not VAT. It is not income tax. It is a separate withholding mechanism - and if you are working as a subcontractor on any construction job, it almost certainly applies to you.

This guide explains exactly what CIS is, how it works, and what it means for your invoices and take-home pay.

What is the Construction Industry Scheme (CIS)?

CIS is an HMRC scheme that changes how subcontractors in construction get paid. Instead of a subcontractor invoicing a contractor and receiving the full amount, the contractor is required to deduct a percentage from the labour element of the payment and send it directly to HMRC on the subcontractor's behalf.

The deduction is not a tax in itself - it is an advance payment against the subcontractor's income tax and National Insurance bill. At the end of the tax year, the subcontractor reconciles their actual tax liability with their tax return. If the CIS deductions were more than they owed, HMRC refunds the difference.

Who does CIS apply to?

CIS applies to businesses and self-employed individuals working in construction in the UK. Specifically:

• Contractors - businesses that pay subcontractors for construction work, or whose average annual spend on construction exceeds £1 million in any 3-year period
• Subcontractors - self-employed tradesmen who work for contractors on construction jobs

A sole trader plumber, electrician, or builder working on jobs through another company or builder is almost always a subcontractor for CIS purposes. If the person paying you is a contractor registered with HMRC, they must apply CIS deductions to your payment.

CIS does not apply to work you do directly for homeowners. If a homeowner hires you directly and pays you directly, CIS does not apply.

What are the CIS deduction rates?

Under CIS, there are three deduction rates depending on your status with HMRC:

Registering as a CIS subcontractor with HMRC is straightforward and immediately reduces your deduction rate from 30% to 20%. There is no reason not to register.

How do I register as a CIS subcontractor?

You register directly with HMRC. The process differs slightly depending on whether you are a sole trader or a limited company:

Sole traders

If you are already registered for Self Assessment, you can register for CIS by calling HMRC's CIS helpline (0300 200 3210) or online through your HMRC online account. You will need your Unique Taxpayer Reference (UTR) and National Insurance number.

Limited companies

Companies register online through HMRC's business tax account using the company UTR and Companies House registration number.

Once registered, HMRC verifies your status with contractors when they check your details - this is how contractors confirm the correct deduction rate to apply.

What is gross payment status?

Gross payment status means HMRC pays you the full invoice amount without any CIS deductions. The contractor does not withhold anything - you receive the full net + VAT.

To qualify for gross payment status, you must pass HMRC's compliance test:

• Your business (or you personally) must have been trading in construction for at least 12 months
• Your tax affairs must be up to date with no significant outstanding liabilities
• Your annual turnover from construction must be at least £30,000 per year (sole trader) or £100,000 per year (partnership / company)

For an established sole trader plumber or electrician with a clean tax record, gross payment status is worth applying for. It improves your cash flow significantly.

How does CIS affect my invoices?

CIS deductions are made from the labour element of your invoice only - not from materials. When you invoice a contractor, you should split your invoice to show:

1. Labour (this is subject to CIS deduction)
2. Materials (this is not subject to CIS deduction)
3. VAT (calculated on the net labour + materials total)

Example: You invoice a contractor for a job at £2,000 labour + £500 materials. You are VAT-registered (20%), and registered for CIS (20% deduction rate):

The contractor sends the £400 CIS deduction to HMRC and provides you with a CIS deduction statement each month. You use this when completing your Self Assessment tax return.

VAT Domestic Reverse Charge for construction - explained

Since March 2021, most construction services supplied by VAT-registered subcontractors to VAT-registered contractors within the CIS scheme are subject to the VAT Domestic Reverse Charge (DRC).

DRC changes who accounts for the VAT. Under the normal VAT rules, you charge VAT to your customer and pay it to HMRC. Under DRC, you do not charge VAT to the contractor at all. The contractor accounts for the VAT directly to HMRC in their own VAT return - you are effectively removed from the middle.

When DRC applies

DRC applies when all three conditions are met:

• Both you (the subcontractor) and your customer (the contractor) are VAT-registered
• The supply is within the scope of CIS - construction services on a building
• Your customer is not an "end user" - they will make onward supplies of construction services on the same project

A main contractor hiring a subcontractor on a residential development, a commercial fit-out, or an infrastructure project is the most common DRC scenario.

When DRC does not apply

DRC does not apply in these situations - charge VAT normally:

• Direct to homeowners: If your customer is not VAT-registered (private individuals are not), DRC cannot apply. Charge VAT at the normal rate.
• End users: If the customer is the final occupier or owner of the building (a business fitting out its own premises, for example) and is not making onward supplies of construction to another party, they are an end user. End users receive normal VAT invoices.
• Intermediary suppliers: A small group of businesses that meet specific conditions are treated as intermediary suppliers - they receive normal VAT invoices and then apply DRC to their own subcontractors. This mainly applies to connected companies.
• Zero-rated or exempt supplies: If the supply itself is zero-rated (new residential construction) or exempt, DRC does not apply.

End user declarations

An end user must notify you in writing that they are the end user. Without this notification, you should apply DRC. If a customer claims end user status without telling you in writing and you charge DRC incorrectly as a result, HMRC's position is that the liability falls on the customer who failed to notify you.

If you are not sure whether your customer is an end user or a contractor, ask before invoicing. A simple written statement from them ("We confirm we are the end user of the construction services supplied on this project") is enough.

How to invoice under DRC

A DRC invoice is different from a normal VAT invoice in two ways:

1. You do not add VAT to the amount due - the invoice total is the net amount only
2. You must include the statement: “Reverse charge: customer to account for VAT to HMRC”

You should also show the VAT amount that would have applied - but clearly marked as not payable by the customer. For example:

The cash flow impact of DRC

Under normal VAT rules, you collected VAT from your customers and held it until your quarterly return - effectively an interest-free float. DRC removes this completely. You receive only the net amount and never handle the VAT at all.

If you were relying on that VAT float for cash flow, DRC changes your working capital position significantly. The contractor gets the benefit instead - they account for the VAT on your behalf and can reclaim it on the same return.

What if you get DRC wrong?

If you charge VAT when DRC should apply (or vice versa), HMRC can assess the correct tax. The penalties depend on whether the error was careless or deliberate. In practice, genuine mistakes are usually corrected through a VAT adjustment. Keep clear records of why you treated each transaction as DRC or non-DRC.

See HMRC's full DRC guidance for the detailed conditions and examples.

How do I claim back CIS deductions?

CIS deductions are reconciled through your annual Self Assessment tax return. When you file your return:

1. Declare your income from all sources, including construction subcontract work
2. Calculate your tax and National Insurance due on that income
3. Offset the CIS deductions your contractors have already paid to HMRC on your behalf
4. Pay the difference (or claim a refund if you overpaid)

Keep all CIS deduction statements your contractors send you. These are your evidence when filing your return.

If your CIS deductions exceed your total tax bill for the year, HMRC will refund the difference. This commonly happens for sole traders with significant material costs, because the deduction is made on the gross labour payment regardless of actual profit.

Key CIS rules to remember

• CIS deductions come off your labour only - not materials
• Register with HMRC as a subcontractor to pay 20% instead of 30%
• Contractors must verify your status with HMRC before paying you
• Your contractor must give you a monthly CIS deduction statement
• CIS and VAT are separate - you still charge VAT unless DRC applies
• All CIS deductions are reconciled through Self Assessment at year end

For the full picture on UK VAT for tradesmen, see our complete UK VAT guide for sole traders.

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