Claiming a CIS refund as a sole trader: the boxes on your 2025/26 return

By Patrick Roper ACA, ICAEW chartered accountant. Last reviewed 1 November 2026. Figures next checked by 1 December 2026.

If you are a sole trader, you claim CIS deductions back by filing your Self Assessment tax return. You record your total pay before deductions as income and the total deductions as CIS deductions; HMRC works out the tax due and refunds the difference to your bank account. The separate CIS refund guidance that ranks first on Google is for limited companies and does not apply to you.

Why the first result is the wrong page

Search "CIS tax refund" and the top result is HMRC's guide for limited companies. That guide is about setting CIS deductions against a company's PAYE and claiming the balance from the employer side of HMRC. If you are a sole trader, none of it applies. Your route is the ordinary Self Assessment return. HMRC's subcontractor guide says it in one line: send in your return as usual, record your pay before deductions as income and the deductions as CIS deductions, and HMRC takes the deductions off the tax you owe. If the deductions are more than the tax, HMRC pays the difference back.

The three entries

1. Turnover. Your total pay before the contractor took anything off, for all contractors, for the tax year 6 April 2025 to 5 April 2026. The gross figure on each monthly payment and deduction statement, added up. Do not include VAT if you are VAT-registered, and do not include amounts the contractor paid you for materials, which are outside the deduction.
2. Expenses. What you spent to do the work: van costs or mileage, fuel, tools, protective kit, phone, public liability insurance, accountancy. These reduce the profit the tax is worked out on.
3. CIS deductions. The total tax the contractors took off, from the same statements. HMRC's own guide to the scheme (CIS 340, section 1.10) points individual traders to the self-employment pages of the return, SA103S or SA103F, where this box sits.

HMRC then calculates income tax and Class 4 National Insurance on the profit, subtracts the deductions already taken, and either sends you a bill or a refund.

What to have before you start

• Your ten-digit Unique Taxpayer Reference, on any HMRC letter.
• The payment and deduction statements. Contractors must give you one within 14 days of the end of each tax month. Photos are fine.
• Bank statements for the year, if any statements are missing. They show what you were actually paid, and the deduction is 20% of the labour element (30% if you never registered).
• A list of expenses with rough amounts. Receipts are better, but a bank record of the payment will usually do.
• Your bank details, so the refund goes to you.

The deadline, and why filing early matters

The 2025/26 return is due by 31 January 2027. There is nothing to stop you filing it from 6 April 2026 onwards, and a return filed in April or May is in a shorter queue than one filed in the last week of January, when everyone files at once. The refund arrives in the order HMRC processes returns.

If something is missing

No statements from one contractor: ask them first. Contractors are required by the regulations to produce them. If the contractor has gone, the Low Incomes Tax Reform Group's CIS page explains how to write to HMRC for the figures it holds, and what other evidence HMRC will accept. If the contractor took the deduction but never paid it over, that is a separate problem with a clear legal answer, covered in the guide on contractors whose deductions do not show up.

Doing it yourself or paying someone

HMRC's online service is free and, for a year with one or two contractors and a short expenses list, it is a sensible choice. A fee buys three things: the expenses checked line by line against what HMRC allows, a return signed by a named chartered accountant, and someone to deal with HMRC if it asks questions. Our fees are on the CIS page, and the refund is paid by HMRC to your account in every case.