Registering for the Construction Industry Scheme

Subcontractors in the UK construction sector must register for the Construction Industry Scheme (CIS) to avoid the default 30% deduction rate applied by contractors. By registering with HM Revenue and Customs (HMRC), the deduction rate on your labour earnings drops immediately to 20%, significantly improving your business cash flow. Registering also opens the pathway to Gross Payment Status, which drops your deduction rate to 0% if you meet specific turnover and compliance tests.

Key Takeaways: Preventing HMRC's 30% deduction rate

To prevent HMRC from deducting his or her tax at the emergency 30% rate, a subcontractor must take direct administrative action. Follow these essential highlights to secure the lower rates:

• Obtain a Unique Taxpayer Reference (UTR) from HMRC before you start work.
• Register as a subcontractor under the Construction Industry Scheme to cut the tax deduction rate to 20%.
• Itemise all invoices by separating labour from materials to avoid tax being taken from material costs.
• Achieve the £30,000 threshold to apply for Gross Payment Status and secure a 0% deduction rate.
• File your compulsory Self Assessment return annually to reconcile your advance payments and claim rebates.

Should you register for CIS as a subcontractor?

While registration under the Construction Industry Scheme is not legally compulsory, choosing not to register means contractors must deduct a punishing 30% from your labour payments.

The massive difference between the 20% registered rate and the 30% unregistered rate directly impacts your monthly operating cash. For instance, on a contract of £50,000, leaving yourself unregistered results in an extra £5,000 being withheld from your bank account throughout the tax year.

These monthly CIS deductions are not additional taxes, but rather advance payments towards your annual Income Tax and National Insurance contributions. Any money withheld is eventually reconciled through your annual Self Assessment return. If HMRC finds that the mid-year deductions exceed your actual tax liability, they will issue a refund after you file your tax return.

What are the three CIS deduction rates for 2025/26?

HMRC applies three distinct CIS deduction rates for the 2025/26 tax year based entirely on the subcontractor's registration status.

It is critical to understand that these deduction rates apply strictly to your labour costs. Any qualifying building materials you purchased to complete the project must be itemised separately and are completely exempt from CIS deductions.

How to register for CIS and get the 20% rate

Registering for the 20% rate requires setting up your official records with HMRC so contractors can instantly verify your business identity.

1. Obtain a Unique Taxpayer Reference (UTR) from HMRC by registering as self-employed via your online Government Gateway account.
2. Log into your Government Gateway account or call the HMRC CIS helpline on 0300 200 3210 to link your UTR to the CIS subcontractor register.
3. Set your business up for Self Assessment as a sole trader, or establish a limited company registered for Corporation Tax, to enable year-end refunds.
4. Complete this entire registration process before your first contract payment so the billing contractor can successfully verify your active status.

How to get to 0% with Gross Payment Status (GPS)

To secure Gross Payment Status and stop contractors from making any tax deductions, you must successfully pass three strict tests administered by HMRC.

Under the Business test, you must prove that you carry out construction work in the United Kingdom and operate through a bank account opened under your official business name. This ensures your operations are transparent and legitimate.

The Turnover test requires that your annual net construction turnover, which excludes VAT and materials, meets specific limits. This threshold is set at a minimum of £30,000 for sole traders, £30,000 per partner for partnerships, and £30,000 per director for limited companies.

Finally, the Compliance test looks at your tax history. You can apply for Gross Payment Status online using form CIS305, and your history is checked on an annual basis.

How to pass the strict CIS compliance test

The compliance test of the Construction Industry Scheme is incredibly strict, meaning even a single late payment or tax return can cause HMRC to strip your status away.

To pass this test, you must file every single Corporation Tax, Self Assessment, PAYE, and VAT return on time. Additionally, all outstanding liabilities must be paid to HMRC by their due dates, leaving no unpaid tax debts on your file.

Staying compliant is critical because HMRC can revoke Gross Payment Status if you fail to meet standards. According to policy changes published in GoV.UK official CIS updates, beginning on 6 April 2026, the period during which a subcontractor is banned from re-applying for Gross Payment Status following a cancellation due to fraud or administrative abuse is extended from 1 year to 5 years.

How to invoice correctly under the Construction Industry Scheme

Subcontractors must raise clear invoices to ensure the contracting company only takes deductions from your actual labour fee.

Your invoices must explicitly separate structural materials from the physical labour costs. If you lump these amounts together in a single line, contractors are legally obliged to deduct CIS tax from the gross total of the invoice, causing you to pay far too much upfront tax.

How do making tax digital (MTD) changes from 2026 affect you?

New legislative changes coming into force starting 6 April 2026 will transform how highly paid subcontractors report their earnings.

Under the new Making Tax Digital for Income Tax guidelines, any sole trader with a gross qualifying income of over £50,000 from self-employment and property must transition away from a single annual filing. These subcontractors must use MTD-compliant software to send quarterly digital financial updates directly to HMRC.