CIS takes a flat 20% or 30% off your labour from the first pound, with no personal allowance and no expenses taken into account. That's why most subbies overpay during the year. Put in your figures below and see roughly how much comes back.
Tax year 6 April 2026 – 5 April 2027. Nothing you type leaves this page.
Worked out as labour × rate. Type the total from your payment statements if you have it.
An estimate, not tax advice. Assumes self-employment is your only income, with no student loan, payments on account or other adjustments. Your Self Assessment return gives the real figure.
A CIS refund is the difference between the CIS your contractors took off during the tax year and the tax and National Insurance you actually owe on your profit. If more was taken than you owe, HMRC pays the difference back after you file your Self Assessment return.
| Step | Amount |
|---|---|
| Labour paid before CIS | £45,000.00 |
| Expenses (tools, PPE, phone, insurance) | −£3,000.00 |
| Mileage: 8,000 miles at 55p | −£4,400.00 |
| Taxable profit | £37,600.00 |
| Income Tax: 20% of £25,030 (profit over £12,570) | £5,006.00 |
| Class 4 NI: 6% of £25,030 | £1,501.80 |
| Tax & NI due | £6,507.80 |
| CIS deducted: 20% of £45,000 | £9,000.00 |
| Estimated refund | £2,492.20 |
| England, Wales & NI | Rate |
|---|---|
| Personal allowance: up to £12,570 | 0% |
| Basic rate: £12,571 – £50,270 | 20% |
| Higher rate: £50,271 – £125,140 | 40% |
| Additional rate: over £125,140 | 45% |
| Scotland | Rate |
|---|---|
| Starter: £12,571 – £16,537 | 19% |
| Basic: £16,538 – £29,526 | 20% |
| Intermediate: £29,527 – £43,662 | 21% |
| Higher: £43,663 – £75,000 | 42% |
| Advanced: £75,001 – £125,140 | 45% |
| Top: over £125,140 | 48% |
The personal allowance shrinks by £1 for every £2 of income over £100,000. Class 4 National Insurance is the same across the UK. Class 2 is no longer compulsory, so it isn't included.
Sole-trader subcontractors claim CIS back through their Self Assessment tax return, not through a separate form. Once the tax year ends on 5 April, you can file your return online. The CIS deducted goes in the self-employment section, and HMRC works out the refund. Keep your monthly payment and deduction statements from each contractor, because they're your proof of what was taken. Read the full step-by-step guide to claiming your CIS refund.
Sources (last checked 23 October 2026): Income Tax rates and allowances — GOV.UK · Scottish Income Tax — GOV.UK · National Insurance rates for the self-employed — GOV.UK · What you must do as a CIS subcontractor — GOV.UK · Simplified expenses: vehicles — GOV.UK
In DayGraft, the refund estimate updates itself from the days, expenses and mileage you log as you go — in both Full Tracking and Simple Hours. There's nothing to add up in April.
The estimate shows the full working: turnover, expenses and mileage, taxable profit, personal allowance, Income Tax, Class 4 National Insurance and the CIS already taken off. If you're owed money, the balance shows in green.
Set your region once in Settings and the estimate uses the right bands for where you live.
Every day entry splits labour from materials, so the CIS figure is only ever worked out on labour, the way HMRC does it.
The automatic refund estimate in the app is a Pro feature (£4.99 a month or £29.99 a year). This web calculator stays free for everyone.
It depends on your labour income, expenses and mileage for the year. As a rough guide, a subbie on £45,000 labour at 20% CIS, with £3,000 expenses and 8,000 business miles, is owed about £2,500 back. Use the calculator above with your own figures to see yours.
It uses the real 2026/27 tax bands, personal allowance and Class 4 National Insurance rates, including Scotland's bands. It's still an estimate. It assumes self-employment is your only income and doesn't include student loans or payments on account. Your Self Assessment return gives the exact figure.
Sole traders claim it through their Self Assessment tax return after the tax year ends on 5 April. Enter your self-employed income, expenses and the CIS deducted, and HMRC works out the refund. You can file online yourself or use an accountant.
No. You can file Self Assessment directly with HMRC for free. Refund companies charge a fee or a percentage of what you're owed for filing it for you. Seeing your own estimate first helps you decide whether that's worth paying.
Costs you have wholly for your work: tools and equipment, protective clothing and PPE, materials you paid for and weren't reimbursed, the business share of your phone, public liability and tools insurance, accountant fees, and business mileage at HMRC's simplified rate. Everyday clothing and ordinary commuting don't count.
Yes. Choose 30% in the calculator. If you're on 30% because you aren't registered for CIS, registering with HMRC drops you to 20%, so less is taken from each payment during the year.
Yes. This web calculator is free, needs no sign-up, and nothing you type leaves your browser. Inside the DayGraft app, the refund estimate that updates automatically from your logged days, expenses and mileage is part of DayGraft Pro, which has a 7-day free trial.
Download it, log tomorrow's day in ten seconds, and see if it earns its place in your pocket. Free to start, no account needed.
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