If you're a sole trader on CIS, the contractor's been taking 20% off your labour all year. Most subbies with normal running costs are owed some of that back. Three numbers and you'll know roughly how much. Free, nothing to sign up to.
Expenses are higher than what you invoiced — check the numbers.
We'll assume the deduction was taken off your labour only, and that roughly a third of what you invoiced was materials. The number moves a fair bit with this, so the statements are always better.
| Profit (invoiced minus expenses) | £0 |
| Tax-free personal allowance | −£12,570 |
| Income tax due | £0 |
| Class 4 National Insurance due | £0 |
| Total you actually owe | £0 |
| CIS already deducted | £0 |
Deducted minus owed is your refund. It's an estimate, not a promise. The return is where the real number comes from.
or I'll send it to you
Pop in a mobile or an email and I'll get it to you.
Or just give me a ringWant to check one invoice instead? CIS deduction calculator →
Because the contractor takes 20% off your labour before you've had a chance to claim anything. That deduction is tax paid up front, on your turnover, not your profit. Once your expenses and your £12,570 tax-free allowance come off, what you actually owe is usually less than what's been taken. The gap is your refund.
Invoiced minus expenses is your profit. Take off the personal allowance, then it's 20% income tax up to £50,270 of profit and 6% Class 4 National Insurance on the same band (40% and 2% above that). Whatever's been deducted under CIS is set against that bill, and anything over comes back to you. This calculator does exactly that sum with 2025/26 and 2026/27 rates, which happen to be the same.
Through your Self Assessment tax return. The tax year ends 5 April, you can file from then, and the refund usually lands two to six weeks after you file. File in April and you've got it by summer. Leave it to January and you're waiting nine months for your own money.
Anything you spent wholly for the business. Materials you bought, tools, PPE, the van (or a share of it), fuel to site, phone, insurance, accountancy, a bit of home office. Not the commute if you've got a fixed base, not your lunch. If you're not sure, ask. Every £100 you can properly claim is roughly £26 back.
Contractors have to give you one every month they pay you. Ask them. If they've gone quiet, your bank statements plus your invoices will show the gap, and HMRC's own records of what the contractor reported can be checked. That's normal, we do it all the time.
Not this one. Ltd companies offset CIS against PAYE through payroll and reclaim what's left after the year end, which is a different process. There's a page on that here.
Yes. Your personal allowance is shared across all your income, so if the job used some of it, the sole-trader profit gets taxed sooner and the refund's smaller. This calculator assumes CIS work was your only income. Message me and I'll do it properly.