Key HMRC dates for sole traders in 2025/26: your tax calendar
Sole traders do not just have one tax deadline. Registration, filing, payment, payments on account, and penalties all sit on different dates. This calendar gives you the 2025/26 rhythm in one place.
6 April 2025: the 2025/26 tax year starts
From this date, income and expenses belong to the 2025/26 tax year. Keep records as you go rather than trying to reconstruct a year of invoices later. If you start trading during the year, note the date you began.
5 April 2026: the 2025/26 tax year ends
This is the cut-off for income and expenses in the 2025/26 return. After this date, you can start preparing the return, checking bank records, and estimating the bill.
5 October 2026: register for Self Assessment
If you need to file for 2025/26 and have not registered before, tell HMRC by 5 October 2026. This gives HMRC time to issue your UTR and activate online services before the filing deadline.
New to the process? Start with How to register as a sole trader with HMRC.
31 October 2026: paper return deadline
Paper returns are less common, but the deadline is earlier than the online deadline. Most sole traders file online because it gives more time and calculates the bill as part of the process.
31 January 2027: online filing and payment deadline
This is the date most people mean when they talk about “the tax deadline.” It is both the online filing deadline and the payment deadline for the balancing payment. If payments on account apply, the first advance instalment for the next year is also due on this date.
31 July 2027: second payment on account
If HMRC asks for payments on account, the second instalment is due by 31 July 2027. This is easy to forget because it does not come with the same filing task as January.
Filing deadline vs payment deadline
Filing and paying are separate obligations. You can file early and pay later, as long as payment reaches HMRC by the deadline. Filing early is often the best cash-flow move because it tells you the number months before money leaves your account.
Late filing penalties
Missing the 31 January online filing deadline normally triggers an automatic £100 late filing penalty, even if no tax is due. Further daily penalties can follow if the return remains late, and late payment can create separate interest and penalties.
If you are already late, use the late filing penalty estimator to understand the rough shape of the cost, then deal with HMRC directly.
A simple planning rhythm
- April: close records for the old tax year and estimate profit.
- May to July: collect missing invoices, receipts, bank interest, and PAYE details.
- August to October: register if needed and draft the return.
- November to January: file online and pay by 31 January.
- February to July: save for and pay the second payment on account if one is due.
Pair this calendar with our payments on account guide so the January and July cash-flow points are planned together.
Official source
Check the live deadlines on GOV.UK before filing: Self Assessment tax return deadlines.