A CIS tax rebate is the refund you get when the deductions contractors have taken from your payments under the Construction Industry Scheme add up to more than the tax you actually owe. You claim it by filing a Self Assessment return that reports your income, your allowable expenses, and the total CIS tax withheld during the year. HMRC compares those figures against your real tax liability, and if you’ve overpaid, the difference comes back to you.
Most subcontractors do overpay. The deduction rate is flat, but your tax bill isn’t.
Why CIS Deductions Usually Leave You Owed Money
Contractors are required to withhold a percentage from the labour portion of each payment they make to you and send it to HMRC as an advance against your income tax and National Insurance.1GOV.UK. Construction Industry Scheme The rate depends on your status:
- 20% if you’re registered as a subcontractor under CIS.
- 30% if you’re not registered.
- 0% if you hold gross payment status.
Those percentages come off every invoice, whatever your actual profit for the year turns out to be.2GOV.UK. What You Must Do as a CIS Contractor – Make Deductions and Pay Subcontractors They ignore your personal allowance (£12,570 for 2026/27), and they ignore every legitimate business expense you’ve paid out over the year. A subcontractor with £35,000 of net profit, sheltered by the personal allowance and reduced further by tools, travel, and insurance, can easily owe far less than the 20% already withheld. The gap is your rebate.
Who Can Claim
Three things need to be true. You must be self-employed; if you’re on a contractor’s payroll and taxed through PAYE, CIS doesn’t apply and any overpayment is handled through the employer’s system.1GOV.UK. Construction Industry Scheme You must have had CIS deductions taken from your payments during the tax year in question. And those deductions must exceed the tax you actually owe once income, personal allowance, and expenses are all factored in.
Limited companies claim through a separate process, not Self Assessment. That’s covered further down.
Get Your Records Together First
Before you open a tax return, pull everything together. The single most important document is the payment and deduction statement your contractor is required to give you within 14 days of the end of each tax month.3GOV.UK. Payment and Deduction Statement It shows your gross pay, the cost of materials, and the exact CIS tax withheld. Collect one for every month you worked. If a contractor hasn’t sent theirs, chase it. HMRC cross-checks your return against what contractors report, and mismatched figures will hold up your refund.
Alongside those statements, keep receipts for every expense you plan to claim: fuel, tools, insurance renewals, phone bills, accountancy fees. HMRC requires you to hold on to these records for at least five years after the 31 January submission deadline for that tax year.4GOV.UK. Business Records if Youre Self-Employed – How Long to Keep Your Records
Expenses That Grow the Rebate
The size of your refund depends on how much taxable profit you report, and expenses are the main lever. HMRC allows you to deduct costs that are wholly and exclusively for business purposes.5GOV.UK. Expenses if Youre Self-Employed – Overview For construction subcontractors, the usual categories are:
- Travel between sites, including fuel, parking, public transport, and van running costs. Your regular commute to a permanent workplace doesn’t count.
- Tools and equipment, including hand tools, power tools, safety boots, hi-vis clothing, and hard hats.
- Public liability and professional indemnity insurance.
- Accountancy fees, bank charges, and tax software.
- The business portion of your mobile phone bill.
- Training that maintains or updates skills you already use in your trade. Courses to learn an entirely new trade don’t qualify.
Every pound of expense you don’t claim is roughly 20p to 40p of refund you don’t get back, depending on your tax rate. Track them as you go; reconstructing a year of spending from memory in January is where money gets lost.
Filing the Self Assessment Return
You claim through the annual Self Assessment. The main form is the SA100, with a self-employment supplement attached. If your turnover was below the VAT threshold, use the short version, SA103S.6GOV.UK. Self Assessment – Self-Employment Short SA103S If it was above, use the full version, SA103F.7GOV.UK. Self Assessment – Self-Employment Full SA103F
On the self-employment page you report your total turnover (the gross amount before deductions or expenses), then list your allowable expenses. There’s a specific box for the total CIS deductions taken from your payments by contractors. That figure has to be right. HMRC’s system compares it automatically against what contractors reported in their monthly returns, and if the numbers don’t match, the return is flagged and the refund stalls. Check every figure against your payment and deduction statements before you submit.
Filing online is faster than paper, gives you an immediate confirmation, and does the arithmetic for you.
Deadlines and Late-Filing Penalties
For the 2025/26 tax year (6 April 2025 to 5 April 2026):
- Paper returns are due by 31 October 2026.
- Online returns are due by 31 January 2027.
Miss the online deadline and the penalties escalate quickly:8GOV.UK. Self Assessment Tax Returns – Penalties
- £100 fixed penalty immediately, even if no tax is owed.
- £10 per day after three months, capped at £900.
- After six months, 5% of the tax due or £300, whichever is greater.
- After twelve months, another 5% of the tax due or £300, whichever is greater.
A return filed a year late can cost £1,600 or more in penalties alone, plus interest on any unpaid tax. Those penalties apply even when HMRC owes you money.
How and When HMRC Pays Out
Once your return is submitted and shows an overpayment, HMRC processes the refund. Electronic filing is significantly faster than paper. HMRC doesn’t publish a guaranteed turnaround for CIS refunds specifically; most straightforward returns are handled within a few weeks, while complex returns, returns filed during the January rush, or returns flagged for review take longer.
One thing catches people out: HMRC may not send you the full refund. If you have a payment on account due within the next 45 days, HMRC will offset your refund against that upcoming bill rather than pay it into your bank account.9GOV.UK. 10GOV.UK. Understand Your Self Assessment Tax Bill – Payments on Account If HMRC calculates payments on account you don’t believe you’ll owe, you can apply through your online tax account to reduce them; be accurate, because interest applies if you undershoot.
Claiming for Previous Years
If you’ve been working under CIS for years without filing, the money isn’t necessarily lost. You can claim refunds for up to four previous tax years. The deadline for each is 31 January four years after the end of that tax year, so for 2022/23 the cut-off is 31 January 2027.
Going back multiple years means a separate Self Assessment return for each, with income figures, expense records, and CIS deduction statements for each one. If you’ve lost older statements, HMRC may be able to confirm what contractors reported, but that isn’t guaranteed and it takes time. Filing year by year is always cleaner. If you have several years to catch up on, an accountant who handles CIS regularly will usually recover enough to justify the fee.
If You Trade Through a Limited Company
Limited companies don’t claim through Self Assessment. You submit a claim directly to HMRC, either online through the Government Gateway or by posting a written request marked “CIS” to HMRC’s processing centre.11GOV.UK. Claim a Refund of Construction Industry Scheme Deductions if Youre a Limited Company Before HMRC will process it, all your PAYE, CIS, and Corporation Tax returns need to be up to date. Outstanding returns bounce the claim back, and this trips up more companies than you’d expect, particularly those that fell behind on monthly CIS submissions during busy periods.
Skipping the Refund Cycle: Gross Payment Status
If waiting months to get your own money back is a strain on cash flow, gross payment status is the alternative. Contractors pay you in full with nothing withheld, and you settle your tax through Self Assessment as normal. To qualify, HMRC applies a turnover test (at least £30,000 a year excluding VAT and materials for a sole trader), a compliance test (tax and National Insurance filed and paid on time), and a business test (work carried out through a UK bank account).12GOV.UK. How to Get Gross Payment Status HMRC reviews the status periodically and can revoke it if your compliance record slips.