How CIS deductions work
| Your CIS status | Deduction from labour |
|---|---|
| Registered subcontractor | 20% |
| Not registered | 30% |
| Gross payment status | 0% — you pay your tax through Self Assessment |
Deductions are taken from the labour part of each payment. The contractor shouldn't deduct from materials, VAT or certain other costs.
Why subcontractors are often owed money
The 20% is taken from your first pound of labour income. But you have a personal allowance (£12,570 for most people in 2025/26) and you can deduct allowable expenses such as tools, van costs, protective clothing and travel. Once those are taken into account, your real tax bill is often lower than what was deducted.
Example: £30,000 of labour, £6,000 deducted under CIS. After £5,000 of expenses and the personal allowance, Income Tax plus Class 4 NI might come to around £3,000–£3,500 — so roughly £2,500–£3,000 could be due back. Illustrative only; your figures will differ.
Useful tool
Use the CIS calculator to estimate your tax against your deductions.
How to claim your refund
- Make sure you're registered for Self Assessment and have your UTR.
- Collect every CIS payment and deduction statement for the tax year (6 April – 5 April).
- Gather receipts for allowable expenses.
- File your return after the tax year ends — you can do it from 6 April, you don't need to wait until January.
- Enter your total CIS deductions on the self-employment pages (SA103).
- Request the repayment in your HMRC account.
Expenses subcontractors often miss
The bigger your allowable expenses, the bigger your refund. Construction workers commonly forget to claim:
- Tools and equipment, and their repair or replacement.
- Van or vehicle running costs (business share), or HMRC's simplified mileage rates.
- Travel to temporary sites — not a permanent workplace.
- Protective clothing, safety boots and hi-vis, plus their cleaning.
- Phone and internet (business share).
- CSCS card renewal and training that maintains your existing skills.
- Accountancy or software fees for your return.
Keep receipts and bank statements. Our allowable expenses checklist covers the rules in full.
Check the materials split
Deductions should only be taken from labour. If a contractor deducted from materials too, ask them to correct it — your statement should show gross pay, materials and the amount deducted separately.File early to get it sooner
The refund is your money. Filing in April or May rather than January means you can have it months earlier. Missing statements? Ask the contractor — they're required to give you one for each month they pay you.
Upload, don't type
On TaxGo you can upload your monthly CIS statements. We read the gross pay and deductions from each one and add them up, so nothing is missed. See our CIS page.