Which records should a CIS subcontractor keep?
A sole-trader subcontractor needs records that support both the business profit calculation and any CIS deductions reported to HMRC.
You should be able to show how your gross construction income, allowable expenses and CIS deductions were calculated from the underlying records.
What income records should you keep?
- Sales invoices.
- Job and contract records.
- Cash receipts.
- Bank transfers.
- Payment-provider information.
- Credit notes or adjustments.
Remember that the income reported for Self Assessment is not simply the net amount remaining after a contractor deducts CIS.
Which CIS deduction records matter?
Keep every Payment and Deduction Statement received from contractors.
These statements help show:
- The contractor who paid you.
- The gross payment.
- Relevant materials reflected in the CIS calculation.
- The amount of CIS deducted.
- The relevant tax month.
See our CIS Deduction Statements Guide.
What expense records should be retained?
Keep invoices, receipts and calculations supporting qualifying:
Tools & equipment
Purchase invoices, repair costs and finance documentation.
Travel
Mileage logs, parking receipts, tickets and site details.
PPE
Receipts identifying protective clothing and equipment.
Other expenses
Insurance, phone, professional fees and other business costs.
What should a CIS mileage log contain?
A useful contemporaneous record should identify:
- The date of travel.
- Starting point and destination.
- Construction site or customer.
- Business reason for the journey.
- Business miles travelled.
Are bank statements enough?
A bank statement proves that money moved but may not explain what the payment was for. Keep invoices, receipts or other evidence that identifies the business purpose.
Why keep material invoices?
Materials can be relevant both to your business expense records and to the contractor's CIS deduction calculation.
Keep supplier invoices so the actual cost and business purpose can be verified.
How should CIS records be reconciled?
Invoice → contractor statement → bank receipt
These records should be capable of being reconciled so you can identify the gross income, CIS withheld and amount actually received.
How long should CIS subcontractor records be kept?
For a sole trader's Self Assessment business records, HMRC's standard rule is at least five years after the 31 January submission deadline for the relevant tax year.
| Record type | General retention position |
|---|---|
| Self-employed business records | At least 5 years after the relevant 31 January submission deadline. |
| CIS evidence used for the tax return | Keep with the business records supporting the Self Assessment figures. |
| Records under an open HMRC enquiry | Longer retention can be necessary while the enquiry remains unresolved. |
| Very late returns | Special retention rules can apply. |
A subcontractor's deduction statements may also be evidence needed to make the Self Assessment business return complete and correct, so the longer income-tax record period can apply.
What if records are lost or destroyed?
Try to replace them using contractor duplicates, supplier invoices, bank records and other available evidence.
HMRC says that if records cannot be replaced, you must make your best effort to provide the figures and identify estimated or provisional amounts on the tax return where required.
Do CIS records need to be digital?
Ordinary CIS registration alone does not mean every subcontractor's records must automatically be digital.
However, Making Tax Digital for Income Tax can separately impose digital record requirements where the individual falls within the MTD rules.
Reviewed & Updated
18 August 2026
2026/27
GO TAX REFUNDS
HMRC Compliance Handbook
CIS Record Keeping FAQs
How long should I keep CIS statements?
Where they support a sole trader's Self Assessment return, keep them with the underlying business records for the relevant Self Assessment retention period.
Do I need every CIS statement?
You should retain statements supporting the deductions reported to HMRC and request duplicates for missing statements where possible.
Are bank statements enough for expenses?
They can support a transaction but often do not establish what the expense was or why it related to the business.
What if I lose a CIS statement?
Ask the contractor for a duplicate. HMRC permits replacement Payment and Deduction Statements.
Official HMRC Sources
GOV.UK — Self-employed business records GOV.UK — How long to keep records HMRC — Income Tax business record retention HMRC — CIS Payment and Deduction StatementsNeed help organising your CIS records?
Go Tax Refunds can help review your contractor statements, income and business expense records.
Get CIS Tax Support