Last updated: 14 October 2026
Are old sales receipts taxable if you add them to current sales?
Yes, but they should be taxed in the right year, not just added to this year’s figures. Under accruals accounting, income is taxed in the period you earned it, when the work was done or goods supplied. Under the cash basis, it’s taxed when you received the money. If you find receipts from an earlier year that weren’t included, you should usually correct the earlier year’s return rather than adding them to the current year.
Which year the income belongs to
| Accounting method | When income is taxed |
| Cash basis (default for most sole traders since 2024/25) | When the money is received |
| Accruals basis (companies and some sole traders) | When the sale is made or work done |
If the earlier return can still be amended
- Self Assessment: you can amend online within 12 months of the 31 January filing deadline. For 2024/25, that’s 31 January 2027.
- Company tax return: you can amend within 12 months of the filing deadline.
After those dates, you tell HMRC about the error by letter or through the Digital Disclosure Service.
Why not just add them to this year?
- The tax rate may be different between years
- HMRC charges late payment interest, 7.75% at present, from the original due date
- Adding them to the wrong year makes your accounts inaccurate
- Penalties may be lower if you correct the error yourself
For small errors, HMRC accepts an adjustment in the current year if the tax difference is minimal and the error was not deliberate. Ask your accountant whether this applies.
Example
Jack, a sole trader using the cash basis, finds £2,600 of cash receipts from March 2025 that he forgot to bank or record. The money was received in the 2024/25 tax year. He amends his 2024/25 return, pays the extra tax and the interest. A penalty is unlikely if he tells HMRC before they find out and the error was not careless.
VAT
If you’re VAT registered, VAT errors up to £10,000 (or 1% of turnover, up to £50,000) can be corrected on your next VAT return. Bigger errors need to be reported to HMRC on form VAT652.
Preventing future errors
- Bank all receipts promptly
- Use accounting software with bank feeds
- Reconcile your sales records with your bank account each month
- Keep copies of invoices and receipts
Common mistakes
- Banking old cash receipts without telling HMRC which year they belong to
- Recording receipts from a previous year as current income in accruals accounts, which gives the wrong profit for both years
- Leaving a known error uncorrected because the amount seems small
Talk to your accountant first
Before amending a return, check the figures with your accountant, as other adjustments may be needed in the same year.
Frequently asked questions
Will HMRC charge a penalty?
Only if the error was careless or deliberate, and penalties are lower if you tell HMRC first.
How far back can HMRC look?
4 years normally, 6 for carelessness, 20 for deliberate errors.
What if it was income for my company?
The company amends its CT600 for the year concerned.
Can I deduct old expenses too?
Yes, also in the year they relate to.
Related: correcting an old tax return error, the cash basis scheme and new consulting income.
Talk to Accotax
Want this handled for you? Our team at Accotax can help with bookkeeping and accounts. See our small business accountants service, or contact us for a free, no-obligation quote.
This page is general guidance based on HMRC rules for the 2026/27 tax year, checked against gov.uk on 14 October 2026. It is not personal advice, so speak to an accountant about your own situation.
