CIS calculator
Work out the Construction Industry Scheme deduction on a payment, then estimate whether you'll get money back at the end of the year.
Your result appears here as you type.
An estimate from the figures you entered. It is not financial advice.
How CIS deductions work
When a contractor pays you for construction work, they take a deduction from the labour part and pass it to HMRC as an advance payment of your tax and National Insurance. You get a payment and deduction statement each month. Keep them, because they're your evidence when you file.
| Your status | Deduction on labour |
|---|---|
| Registered subcontractor | 20% |
| Not registered | 30% |
| Gross payment status | 0% |
How the refund estimate is calculated
Your real tax bill is based on profit: what you were paid less your expenses. The calculator works out income tax and Class 4 NI on that profit with 2026/27 rates, then takes it away from the CIS already deducted. A positive figure is roughly what HMRC should repay. It assumes CIS work is your only income. If you have a job as well, your refund will usually be smaller.
Worked example: a bricklayer's year
Kyle is paid £40,000 in the year: £32,000 of labour and £8,000 for materials he bought. CIS at 20% on the labour comes to £6,400. His expenses, including those materials, are £13,000.
- Profit: £27,000
- Income tax: £2,886, and Class 4 NI: £865.80
- Real bill: £3,751.80
Kyle has already had £6,400 deducted, so he can expect a refund of about £2,648 after filing his return.
Questions people ask
What are the CIS deduction rates?
20% if the subcontractor is registered for CIS, 30% if they are not registered, and 0% if they hold gross payment status. The deduction is taken from the labour part of the payment only.
Is CIS taken off materials and VAT?
No. The contractor deducts CIS from labour only. Materials the subcontractor bought for the job, and VAT, are paid in full. If an invoice doesn’t split them out, the contractor may take the deduction from the whole amount.
Will I get a CIS tax refund?
Often, yes. CIS is taken at 20% from your first pound of labour, but you also have a £12,570 personal allowance and expenses to deduct. When you file your Self Assessment return the CIS taken is set against your tax and Class 4 NI, and any excess is refunded.
When can I claim my CIS refund?
Sole traders claim through their Self Assessment return after the tax year ends on 5 April. You can file from 6 April, and refunds usually arrive within a few weeks of a correct online return. Limited companies reclaim through their monthly payroll submissions instead.
How do I register for CIS?
Sole traders register for CIS as a subcontractor through HMRC online or by phone, once they are registered for Self Assessment. Until you are registered, contractors must deduct 30%.
Sources
Rates and review
Uses rates for the 2026/27 tax year. Figures last checked against the sources on 25 October 2026.
Written by author to be named. Reviewed by qualified reviewer to be named.
See how we calculate and the disclaimer. Spotted a wrong figure? Report a problem.