CIS tax refund & deduction calculator
Two quick tools: work out what gets deducted from a payment, or estimate what you're owed back for the tax year. Both are free, and both are estimates, not a substitute for an actual return.
Two quick tools: work out what gets deducted from a payment, or estimate what you're owed back for the tax year. Both are free, and both are estimates, not a substitute for an actual return.
Work out what a contractor will deduct from a labour payment before you're paid.
CIS is only deducted from labour, not materials, so materials are added back in full. This assumes the materials cost has been separately identified and agreed with the contractor.
Estimate whether you're due a refund once your CIS deductions are reconciled against your actual tax bill.
Not sure what counts? See our allowable expenses guide.
Based on 2026/27 Income Tax and Class 4 National Insurance rates for England, Wales and Northern Ireland. Scottish rates differ and aren't covered here.
We'll check your real CIS deduction history and file the return that gets any refund moving.
It's a good working estimate, not a substitute for a full tax return. It uses current Income Tax and Class 4 National Insurance rates for England, Wales and Northern Ireland, but doesn't account for other income, pension contributions, student loan repayments or other reliefs that could change your actual figure.
No. Scotland has different Income Tax bands and rates to the rest of the UK, so the refund estimate here won't be accurate for Scottish taxpayers. The deduction calculator (CIS rates are UK-wide) still applies.
CIS deductions are based on your gross labour payments, but tax is only due on your profit after allowable expenses. Most of the refund subcontractors are owed comes from this gap: you're deducted at 20% of gross pay, but only actually owe tax on a smaller, expenses-reduced profit figure.
Tools, protective clothing, vehicle and mileage costs, materials you've paid for yourself, insurance, phone and admin costs, and relevant training are the common ones. We cover this in more detail in our allowable expenses guide.
A refund only happens once you file an accurate Self Assessment return that reconciles your CIS deductions against what you actually owe. HMRC doesn't work it out or pay it automatically. We can file this for you and make sure nothing's missed.