What is the difference between 20% and 30% CIS?

20% is the standard rate for subcontractors registered for CIS who can be verified by the contractor (net payment status). If you are not registered, or the contractor cannot verify you, they must deduct 30% instead. Registering for CIS to move onto the 20% rate is free.

I have gross payment status — do I still get a CIS refund?

No. With gross payment status contractors pay you in full with nothing deducted, so there is nothing to refund — you pay all your tax and National Insurance at the end of the year through Self Assessment instead.

Construction Industry Scheme · subcontractors · Self Assessment

CIS tax refund calculator

Q: How much CIS tax will I get back?

It depends on your labour income and expenses, but because 20% is taken off your whole turnover — before expenses and before your £12,570 tax-free allowance — most subcontractors on a normal income get a four-figure refund. Higher earners whose profit runs into the 40% band can instead owe a small balance.

If you're a construction subcontractor, your contractors take 20% (or 30% if you're not registered) off your labour before you're paid. That's deducted from your turnover, before expenses and before your tax-free allowance — so most subcontractors have overpaid and are owed a refund. Work out roughly how much you'll get back for the 2026/27 tax year. It runs in your browser; nothing is sent anywhere.

Your CIS year (6 April 2026 – 5 April 2027)

Use the totals from your monthly CIS statements and your records. Enter labour only — CIS isn't deducted from materials, plant hire or VAT.

CIS payments received (labour, before deductions) the gross labour figure your contractors deducted CIS from

Your CIS status sets the deduction rate that was taken at source

Business expenses materials, tools, fuel, van, insurance, phone — the costs of doing the work

Other taxable income this year optional — a PAYE salary or other work, so the band is right

Tax already paid on that other income optional — PAYE tax shown on your P60/payslips

Why subcontractors are usually owed money

CIS deductions are taken off your gross labour — before you knock off a penny of expenses and before your £12,570 personal allowance. But HMRC only actually taxes your profit, above that allowance. So the tax taken at source is almost always more than your real bill, and the difference comes back to you after you file.

Registered subcontractor20% deducted
Not registered or not verified30% deducted
Gross payment status0% — you pay it all at year end

Deductions are only on labour

Contractors don't take CIS from what you invoice for VAT, materials, plant hire or consumable stores you paid for yourself. Enter only the labour part above, and put your material and tool costs in with your expenses.

How the refund is worked out

Exactly the way HMRC does it on your Self Assessment return: your real tax and National Insurance are calculated on your profit, then the CIS already deducted is taken off. Overpaid, and you get a refund; underpaid — usually only higher earners — and there's a balance to pay by 31 January.

Income tax on profit above £12,57020% / 40% / 45%
Class 4 National Insurance (profit over £12,570)6% then 2%
Less CIS already deducted20% / 30% of labour

This is a realistic estimate on the standard rates. Your exact refund depends on your full return — other income, reliefs, pension contributions and any payments on account already made.

Common questions

How much CIS tax will I get back?

It depends on your labour income and your expenses, but because 20% is taken off your whole turnover — before expenses and before your £12,570 tax-free allowance — most subcontractors on a normal income get a four-figure refund. The calculator above estimates your own figure. Higher earners whose profit runs into the 40% band can instead owe a small balance.

When can I claim my CIS refund?

After the tax year ends on 5 April. You claim it by filing your Self Assessment return: put your full invoice income in, and the CIS deducted in the "CIS deductions" box. HMRC works out the difference and repays any overpayment. You can file from 6 April, and the sooner you do, the sooner the refund arrives.

Is CIS deducted from materials?

No. Contractors only deduct CIS from the labour part of your invoice. Amounts for VAT, materials, plant hire and consumable stores you paid for directly are excluded. That's why you should enter only your labour income above, and claim your material costs as expenses.

What's the difference between 20% and 30% CIS?

20% is the standard rate for subcontractors who are registered for CIS and can be verified by the contractor ("net payment status"). If you're not registered, or the contractor can't verify you, they must deduct 30% instead. Registering for CIS to move onto the 20% rate is free and worth doing.

Do CIS deductions cover my National Insurance too?

Yes. HMRC treats CIS deductions as advance payments towards both your Income Tax and your Class 4 National Insurance. When you file, your Class 4 NI is added to your income tax to work out the total, and the CIS already deducted is offset against the whole lot.

I have gross payment status — do I still get a refund?

No. With gross payment status contractors pay you in full with nothing deducted, so there's nothing to refund — you pay all your tax and National Insurance at the end of the year through Self Assessment instead. This calculator is for subcontractors who've had 20% or 30% taken off.

More free tools

Tax bill calculator →Your full Self Assessment bill — income tax, Class 4 NI and payments on account. Mileage & expenses →Claim the van miles and costs that cut your taxable profit — and grow your refund. Self Assessment deadlines →When to register, file and pay so you don't miss your refund window.

Claim every pound back — get your figures straight first

Your CIS refund is only as big as the expenses you remember to claim and the income you record accurately. Our Self Assessment Tax Estimator works out your real bill and refund end to end, so you can see the number before you file — and know the CIS deductions have been offset properly.

Self Assessment Tax Estimator 2026/27 — income tax, Class 4 NI, CIS deductions offset, payments on account and a monthly set-aside, from your income and expenses.
Freelancer Invoice Tracker & Log — paid, outstanding and overdue at a glance, so your income figure is right when you claim.
Freelance Day-Rate & Profit Calculator — the day rate you need to hit your take-home.
Rental Property ROI & Yield Calculator — the real after-Section-24 return on a let.

Excel and Google Sheets. Working formulas, not just formatting. Built and checked by us, with AI assistance, and every calculation verified.

Get the Tax Estimator — £9 →

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