Self Assessment deadlines for the self-employed
The dates that matter for your 2025/26 tax return, what payments on account are, and what happens if you miss a deadline.
Checked against official guidance on 5 November 2026.
The key dates
| Date | What’s due |
|---|---|
| 5 October 2026 | Tell HMRC you need to file a return for 2025/26, if you haven’t registered for Self Assessment before |
| 31 October 2026 | Paper tax return (HMRC must receive it by 11:59pm) |
| 31 January 2027 | Online tax return, and paying any tax you owe for 2025/26 (by 11:59pm). Also your first payment on account for 2026/27, if you have to make them |
| 31 July 2027 | Your second payment on account for 2026/27 |
Most people file online, which gives you until 31 January. Leaving it to the last week is when the HMRC phone lines and website are busiest.
Payments on account, explained
Payments on account are advance payments towards next year’s tax bill, paid in two halves on 31 January and 31 July. Each one is half of the tax you owed for the year just gone.
They catch people out in their first profitable year, because the January bill includes the whole of last year’s tax plus the first half of next year’s. For example, if you owe £4,000 for 2025/26, you’d pay £6,000 on 31 January 2027 (the £4,000 plus a £2,000 first payment on account) and £2,000 on 31 July 2027.
You don’t have to make payments on account if last year’s tax bill was less than £1,000, or if more than 80% of the tax you owed was already paid another way, such as through PAYE.
If you miss a deadline
- Filing late: a £100 penalty straight away.
- More than 3 months late: £10 a day on top, up to £900.
- More than 6 months late: a further 5% of the tax due or £300, whichever is more.
- More than 12 months late: another 5% or £300, whichever is more.
- Paying late: penalties of 5% of the unpaid tax at 30 days, 6 months and 12 months, plus interest on what you owe.
Getting your numbers ready
- Your total income from self-employment for 6 April 2025 to 5 April 2026, based on the invoices you sent.
- Your allowable business expenses for the same period, grouped by type, with the receipts to back them up.
- Your Unique Taxpayer Reference (UTR) and your HMRC online account details.
- Any other income you need to report, such as from a job, property or savings.
If your invoices and expenses already live in one place, the return is mostly copying totals across. Freelance Ops keeps every invoice and expense (with its receipt) together, and on the Freelancer plan shows your income, expenses and profit for the UK tax year. It doesn’t file your return: you still do that through HMRC or your accountant.
Quick answers
When is the Self Assessment deadline for 2025/26?
31 January 2027 for online returns and for paying what you owe, both by 11:59pm. Paper returns are due earlier, by 31 October 2026.
What are payments on account?
Advance payments towards next year’s tax, each half of last year’s bill, due on 31 January and 31 July. You don’t make them if last year’s bill was under £1,000 or more than 80% of your tax was paid another way, such as PAYE.
What’s the penalty for filing my tax return late?
£100 straight away, then £10 a day after 3 months (up to £900), then 5% of the tax due or £300 (whichever is more) at 6 months and again at 12 months. Paying late adds separate penalties and interest.
Does Making Tax Digital change this?
For sole traders with turnover over £50,000 it already has, from April 2026, and it reaches those over £30,000 from April 2027. You still file a tax return by 31 January, but you also send quarterly updates. See our Making Tax Digital guide.