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CIS Refund Estimator

Estimate what you might get back at Self Assessment — compare CIS deductions already suffered against the tax and National Insurance actually due on your profit.

Refund worksheet

SA-CIS REF
Income for the tax year
£
Your total labour earnings across all contracts this tax year — not including materials you were reimbursed for.
£
Tools, fuel, van costs, materials you paid for yourself, insurance, accountancy fees, etc.
£
Add up the deductions shown on the payment and deduction statements your contractor(s) gave you.
Taxable profit£0.00
Personal allowance used£0.00
Estimated Income Tax due£0.00
Estimated Class 4 NI due£0.00
Total estimated liability£0.00
Estimated refund
£0.00
Estimate
Rates checked · 2026/27 tax year

Why subcontractors are often owed a refund

Contractors deduct CIS at a flat 20% (or 30%) of your labour income, with no regard for your personal allowance or business expenses. Most subcontractors have both — a tax-free personal allowance of £12,570, plus deductible costs like tools, fuel, van running costs and insurance. Because CIS is deducted before any of that is accounted for, subcontractors frequently pay in more through the year than they actually owe, and reclaim the difference through Self Assessment.

How this estimate is built

This is a simplified model for a single self-employment income with no other complicating factors — it will be less accurate if you have other income, made a loss, or your circumstances involve higher-rate tax, Marriage Allowance, or Student Loan deductions.

Common questions

When can I claim my CIS refund?

After the tax year ends (5 April), once you've filed your Self Assessment return — the earliest realistic point is April, once all your CIS statements for the year are in.

What records do I need?

Every CIS payment and deduction statement from each contractor you worked for, plus receipts or records for any expenses you're claiming.

What if I operate through a limited company?

Limited companies don't reclaim CIS through Self Assessment — instead, CIS suffered is offset against the company's PAYE, NI and CIS liabilities as a subcontractor, reported through the Employer Payment Summary.