CIS Tax Calculator UK
Calculate your net pay after Construction Industry Scheme (CIS) tax deductions. Free calculator for UK subcontractors working under CIS.
Calculate Your CIS Deduction
Your labour charge before any deductions
Registered with HMRC - standard rate
CIS is not deducted from materials
Your Payment Breakdown
What this means:
- • The contractor will pay you £1600.00
- • They send £400.00 to HMRC as advance tax payment
- • You'll claim this back (if overpaid) when filing Self Assessment
💡 Pro Tip
Keep all your CIS statements from contractors. You'll need them for your Self Assessment tax return. Many subcontractors get refunds because their CIS deductions exceed their actual tax owed.
⚠️ Not Tax or Accounting Advice
This guide is for informational purposes only and does not constitute tax advice, accounting advice, or professional financial services. Tax laws, allowances, and HMRC requirements change frequently.
Before making any tax decisions or filing returns: Consult a qualified accountant or tax advisor who can review your specific circumstances. What's mentioned here may not apply to your situation, and regulations may have changed since publication.
Official source: HMRC (gov.uk/hmrc)
What is CIS Tax?
The Construction Industry Scheme (CIS) is an HMRC tax system that requires contractors to deduct tax at source from subcontractors' payments. If you work as a subcontractor in the UK construction or trades industry, your contractor must deduct CIS tax from your invoice before paying you.
CIS Deduction Rates 2025/26
- 20% standard rate - For registered subcontractors verified with HMRC
- 30% higher rate - For subcontractors not registered or not verified with HMRC
- 0% gross payment status - For established businesses that pass HMRC's compliance tests (must apply separately)
How to Use This CIS Calculator
- Enter your gross invoice amount (before any deductions)
- Select your CIS deduction rate (20% or 30%)
- Optionally include materials cost (CIS is not deducted from materials)
- See your net payment instantly - this is what hits your bank account
Important: Materials Are Not Subject to CIS
If you invoice for both labour and materials separately, CIS is only deducted from the labour portion. For example: £1,000 labour + £500 materials = CIS deducted only from £1,000. Always show materials as a separate line item on your invoices.
Example CIS Calculation
Plumber invoices contractor for bathroom refit:
- • Labour: £2,000
- • Materials: £800
- • Total invoice: £2,800
- • CIS rate: 20% (registered subcontractor)
Calculation:
- • CIS deduction: £2,000 × 20% = £400
- • Materials (no CIS): £800
- • Net payment received: £2,400
What Happens to Your CIS Deductions?
The contractor sends your CIS deductions to HMRC on your behalf. These payments count as advance tax payments towards your Self Assessment tax bill at the end of the year.
You'll receive a CIS statement each month showing how much was deducted. Keep these - you'll need them when filing your tax return. Many subcontractors get tax refunds because their CIS deductions exceed their actual tax liability.
Stay on Top of CIS Admin
Move from guesswork to a simple system
Use this calculator to sanity‑check deductions, keep CIS statements organised, and make it easier to pull the numbers your accountant needs at year end.
Try Toolfy Free →Related Resources
- Complete CIS Tax Guide for Subcontractors 2026 - Everything you need to know about CIS registration, rates, and compliance
- UK Trades Tax Deduction Checklist 2026 - Every tax deduction you can claim as a UK subcontractor
- Sole Trader vs Limited Company for Trades 2026 - Should you incorporate? (CIS works differently for limited companies)
Frequently Asked Questions
Do I have to register for CIS?
Yes, if you work as a subcontractor for construction or trades contractors. Registration is free and reduces your deduction rate from 30% to 20%. Register at gov.uk/cis-subcontractor.
Can I get gross payment status?
Possibly, but it's difficult. You must pass HMRC compliance tests including: turnover of at least £30,000/year, clean tax record for 12 months, and pass business checks. Most new subcontractors won't qualify for at least a year.
What if my contractor deducted the wrong amount?
Check your CIS registration status first. If you're verified for 20% but were charged 30%, contact the contractor immediately with your UTR number. They can correct it and refund the difference. If they've already paid HMRC, you'll claim it back via Self Assessment.
Do I still pay National Insurance if I'm under CIS?
Yes. CIS only covers income tax deductions. You're still responsible for Class 2 and Class 4 National Insurance contributions when you file your Self Assessment tax return.
Bring CIS, jobs, and invoices together
When you're ready to move beyond spreadsheets, Toolfy helps you keep jobs, quotes, and invoices in one place so it's easier to stay organised at CIS time.