How to Claim Your CIS Tax Refund (Rebate) in the UK — 2026 Guide

If you're a subcontractor working under CIS, there's a strong chance HMRC is sitting on money that belongs to you. Every time a contractor deducts 20% (or 30% if you're not registered) off your labour, that money goes to HMRC as an advance on your tax bill. At the end of the year, once your actual tax and National Insurance are worked out, those deductions often add up to more than you actually owe — and the difference comes back to you as a CIS tax refund.

This is your plain-English guide to claiming it: how it works, what you need, and when the money actually hits your account.

Why You're Probably Owed a Refund

Here's the thing most subcontractors miss. CIS deductions are taken off your full labour figure before any expenses are accounted for. But you only actually pay tax on your profit — your income after expenses like tools, van, fuel, insurance and materials.

So if you invoiced £40,000 in labour over the year and had 20% deducted, that's £8,000 sent to HMRC. But once you knock off your personal allowance and your legitimate business expenses, your real tax and NI bill might only be £4,000–£5,000. The rest is yours back. For a lot of full-time subbies that refund runs into the thousands every single year.

How the CIS Refund Actually Works

There's no separate "refund form." Your CIS refund comes out of your Self Assessment tax return. The process is:

You add up all the CIS deductions taken from you across the tax year (6 April to 5 April). You report your total income and all your allowable expenses on your Self Assessment return. HMRC works out what you actually owe in tax and NI. They subtract what you've already paid through CIS deductions. If you've overpaid — which most subbies have — the difference is refunded.

That's why keeping every CIS deduction statement matters. Each statement from a contractor shows what they deducted, and that total is what you reclaim.

What You Need Before You Claim

To get your full refund without delays, have these ready:

Your UTR number and Government Gateway login. Every CIS deduction statement for the year (the monthly slips contractors should give you). Records of your income — invoices raised. Records of your expenses — receipts for tools, fuel, materials, insurance, phone, and so on.

If a contractor never gave you a deduction statement, chase it. You're legally entitled to one, and without it you could end up under-claiming.

When Will You Get Your CIS Refund?

You can file your Self Assessment return any time after the tax year ends on 5 April. The earlier you file, the earlier your refund lands — there's no reason to wait until the January deadline if HMRC owes you money.

Once you've filed, a CIS refund usually takes a few weeks to process, though it can be quicker if your return is clean and there are no security checks. HMRC may hold it up if your figures look off or your records don't match what contractors have reported, which is another reason to keep everything tidy.

Mistakes That Cost Subcontractors Money

A few things that regularly leave subbies out of pocket:

Not claiming expenses properly — every pound of legitimate expense increases your refund. Losing or never collecting deduction statements. Filing late and triggering penalties that eat into the refund. Staying on 30% because you never registered — that's an extra 10% held back for no reason. Guessing figures instead of keeping records, which risks an HMRC enquiry.

How Dayrates Helps

The whole refund process gets a lot easier when your invoices, CIS deductions and receipts are all in one place instead of scattered across a notebook, a shoebox and your phone. Dayrates tracks your CIS deductions automatically as you invoice, stores your receipts, and pulls everything into a one-tap monthly bundle you can hand straight to your accountant at refund time. Try it free for 14 days — no card needed.

A CIS refund isn't a bonus or a fluke. It's your own money coming back. The subbies who keep good records get it quickly and in full; the ones who don't either wait months or leave money behind.