Free Tool
CIS Tax Calculator
Calculate CIS deductions on labour and materials instantly. Use shareable URLs for review, export calculations to CSV, and keep payment checks consistent across your team.
Reviewed on 20 February 2026.
CIS Deductions Calculator
Calculate CIS deductions for subcontractor payments using gross amount, materials exclusion, and verification status.
Enter the invoice amount before VAT.
Materials supplied by subcontractor and excluded from CIS deduction.
Calculation Breakdown
Gross £10000.00 with £2000.00 materials leaves £8000.00 labour. At 20%, CIS deduction is £1600.00 and net payment is £8400.00.
Remember to include this deduction in your monthly return
This deduction of £1,600.00 should be included in your monthly CIS return to HMRC by the 19th of the following month.
This calculator provides guidance only. CIS rules depend on contract structure and HMRC verification status at payment time.
- VAT is excluded from CIS deduction calculations
- Verify subcontractor status with HMRC before each payment run
- Retain evidence of verification and deduction records for audit
- Consult your accountant for contract-specific treatment
How the calculation works
Formula: (Gross Payment - Materials) × CIS Rate. Materials are excluded from CIS if evidenced correctly. The resulting deduction is withheld from the gross amount to get net payment.
- • Verified subcontractor rate: 20%
- • Unverified subcontractor rate: 30%
- • Gross payment status rate: 0%
Worked UK scenarios
Verified subcontractor (20%)
Gross £10,000 with £2,000 materials leaves £8,000 labour. CIS deduction is £1,600 and net payment is £8,400.
Unverified subcontractor (30%)
Gross £6,500 with £1,000 materials leaves £5,500 labour. CIS deduction is £1,650 and net payment is £4,850.
Gross payment status (0%)
Gross £4,000 with £500 materials leaves £3,500 labour. CIS deduction is £0 and net payment remains £4,000.
Common CIS mistakes
- • Deducting CIS from VAT or unverified material values.
- • Applying old verification status without fresh HMRC checks.
- • Missing monthly return deadlines due to poor payment records.
Keep these records for audit
- • HMRC verification evidence and deduction rate confirmation.
- • Invoices separating labour and material values.
- • Monthly CIS return submissions and payment statements.
CIS calculator FAQs
Do CIS deductions apply to VAT?
No. CIS applies to the labour element excluding VAT.
Can I deduct CIS from materials?
No. Materials supplied by the subcontractor are excluded from CIS deductions when evidenced properly.
How often do I submit CIS returns?
Monthly. CIS returns are typically due by the 19th of the month following the tax month.