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How much CIS will you get back?
Contractors take 20% off all your labour, but you only owe tax on your profit, so many subcontractors get some back. Put in a normal week to see roughly how much.
Before CIS comes off. Leave out materials and VAT.
Roughly what should come back
£2,438
- CIS taken off: £7,360.00
- Tax and NI on your profit: £4,922.00
- Profit £31,500.00, after £3,300.00 for miles and your costs
Don’t leave £2,438 with HMRC
Your refund only comes back if your expenses and miles are on your tax return. Kev keeps them on your phone, adds up your CIS statements and shows your refund building all year. Free plan, no card needed.
Save my refund in KevWe’ll keep this result for you in Kev. Just your email, no card.
Costs: tools, workwear, phone, training, insurance. Miles at HMRC’s 55p then 25p, so leave van fuel and repairs out of costs.
A rough guide for the 2026 to 2027 tax year, at gov.uk rates. It assumes CIS work is your only income. HMRC works out the real figure from your Self Assessment return.
Tax and mileage rates checked on gov.uk on 6 November 2026.
How it works it out
- Your labour for the year: a week’s labour times the weeks you worked.
- CIS taken off: 20% of that (30% if you’re not registered). That’s tax you’ve already paid.
- Your profit: labour less your costs and your miles at HMRC’s rate (55p a mile for the first 10,000, then 25p).
- The tax you really owe: Income Tax and Class 4 National Insurance on that profit, with the first £12,570 tax-free.
- CIS taken off less the tax you owe is roughly what comes back.
More on deductions, statements and gross payment status in CIS for subcontractors explained, and on what you can claim in what expenses can I claim.
Kev for CIS trades: builders, painters and decorators, carpenters and joiners, roofers, plasterers, tilers, bricklayers, scaffolders, groundworkers, dryliners.
Questions
Why do so many CIS subcontractors get a refund?
Contractors take 20% off all your labour, but your real bill is worked out on your profit, after your expenses and miles, and the first £12,570 of profit has no Income Tax on it. So the 20% taken off is often more than you owe, and HMRC pays back the difference.
How do I claim my CIS refund?
Send your Self Assessment tax return for the year. Put your pay before CIS as income, the total CIS taken off as deductions, and your expenses. HMRC takes the deductions off your bill and pays back anything over. You can send the return from 6 April, once the tax year ends.
Do I need to pay a refund company?
No. Anyone can send their own return on gov.uk for free, and HMRC pays the refund straight to you. Some people use an accountant or a refund firm, who charge for it. Either way, the refund depends on having your CIS statements, expenses and miles written down.
What can I claim as expenses on CIS?
Costs you have only for work: tools, workwear and PPE, the business part of your phone, training, insurance, and travel to sites (at the HMRC mileage rate, or the real running costs of your van, not both). Not your normal clothes, lunch, or travel to a permanent workplace.
How accurate is this calculator?
It is a rough guide. It uses the 2026 to 2027 Income Tax and Class 4 National Insurance rates from gov.uk, and assumes CIS work is your only income and you claim nothing else, like pension payments or Marriage Allowance. HMRC works out the exact figure from your return.
Sources
Watch your refund build all year
Add each monthly CIS statement, log receipts and miles as you go, and Kev keeps a running refund figure on your phone, ready for your tax return. Free plan, no card needed.