CIS maths is easy to get wrong and expensive to get wrong: the deduction rate depends on verification status, the deduction applies to labour but not materials, and HMRC expects it all documented.
What you get
- Record subcontractor verification status and the matching deduction rate
- Automatic calculation of labour amount, deduction and net payment
- A clear record per payment for your CIS returns
- Works alongside your subcontractor records
How it works
1
Verify once
Record each subcontractor’s verification status — it drives the rate applied.
2
Enter the payment
Split labour and materials; CertBox calculates the deduction and net payment.
3
Return without dread
Payments are recorded with their deductions, ready for your monthly return.
Common questions
Does CertBox file my CIS return with HMRC?
No — it calculates and records the deductions so your return (or your accountant’s) starts from accurate numbers.
Does it handle gross payment status subcontractors?
Deduction rates follow the verification status you record, including where no deduction applies.