Tax year 6 April 2025 to 5 April 2026
The dates that
matter.
The tax year ends on 5 April. The return for that year, and the tax, are due the following January. These are the dates for the 2025–26 tax year. [1]
| Deadline | What's due |
|---|---|
| 5 October 2026 | Register for Self Assessmentif you need to file for 2025–26 and are new to it, or need to register again |
| 31 October 2026 | Paper tax returnif you file on paper rather than online |
| 30 December 2026 | Online return, if you want tax collected through your PAYE codefor tax under £3,000 where you also have employment or pension income, subject to HMRC’s eligibility rules [6] |
| 31 January 2027 | Online tax return, balancing payment and first payment on accountthe main deadline for most people |
| 31 July 2027 | Second payment on accounttowards the 2026–27 tax year, if payments on account apply to you |
If you started self-employment or letting property during 2025–26 and haven't told HMRC, the 5 October registration deadline is the one to act on now. [4]
Using Making Tax Digital for Income Tax?
If you joined MTD for Income Tax in April 2026, your 2025–26 return is still filed the usual way, by 31 January 2027, and the dates above apply. Your first MTD tax year is 2026–27: quarterly updates during that year, then a return through software by 31 January 2028. The 31 January payment date stays the same. Our Making Tax Digital guide explains who's in scope.
What missing a deadline costs.
HMRC charges separate penalties for filing late and for paying late, and they add up. [2]
- 1 day late
- £100, even if you owe no tax
- 3 months late
- £10 a day for up to 90 days, on top
- 6 months late
- 5% of the tax due or £300, whichever is more, on top
- 12 months late
- A further 5% or £300, whichever is more
Under the standard late-filing rules, a return filed a year late with £5,000 of tax due attracts £1,600 in filing penalties once the 12-month penalty applies: £100 + £900 + £300 + £300. Late-payment penalties and interest are separate.
Late payment is charged separately: 5% of the unpaid tax once it's 30 days late, another 5% at six months and another at twelve months, plus daily interest from the due date. If you can't pay in full, contact HMRC promptly about a payment plan to limit further charges.
If you joined MTD for Income Tax in April 2026, the usual Self Assessment penalties above still apply to your 2025–26 return due on 31 January 2027. The MTD rules apply from your first MTD tax year, 2026–27, whose return is due on 31 January 2028: a points-based system for late submissions, with a financial penalty once you reach the points threshold. HMRC has said it will not apply penalty points for late quarterly updates during 2026–27, but every update must still be sent before the return can be filed. [5]
Already late? File as soon as you can to limit further penalties. If you also owe tax, interest continues until it is paid. If there's a genuine reason, such as serious illness or bereavement, you can appeal, and we'll help you put the appeal together.
Payments on account, explained.
Payments on account usually apply unless your previous year's Self Assessment bill was under £1,000, or more than 80% of your tax was collected at source. Where they apply, HMRC asks you to pay next year's tax in advance: half by 31 January and half by 31 July, each based on last year's bill. [3]
- Tax due for 2025–26
- £4,000
- Payments on account already made for 2025–26
- £3,000
- Balancing payment due 31 January 2027
- £1,000
- Plus first payment on account for 2026–27, due the same day
- £2,000
The example assumes the whole bill is tax on which payments on account are calculated; some parts of a Self Assessment bill are not. The first January after a good year is the one that catches people out: the balancing payment and the next payment on account land together. Once we have your records, we can work out what you need to set aside.
If you expect to earn less next year, payments on account can be reduced, but reduce them too far and HMRC charges interest on the shortfall. We'll work out a sensible figure with you.
What to have ready.
The earlier your records reach us after 5 April, the earlier you know the bill. This is the usual list:
- Your Unique Taxpayer Reference and any relevant HMRC letters. We’ll explain how to authorise us as your tax agent; do not send us your HMRC password or security codes.
- Sales invoices or takings records, and business expense receipts, for 6 April 2025 to 5 April 2026.
- Business bank statements for the year.
- CIS deduction statements, if you're a subcontractor.
- Rental income and expense records, and letting agent statements, if you're a landlord.
- P60s, P45s and P11Ds from any employment, and pension statements.
- Bank interest, dividend vouchers and details of any assets sold.
- Student loan, pension contribution and Gift Aid details.
Missing something? Send what you have. We'll tell you what else is needed and how to get it. Our Self Assessment service explains how we work.
Check the detail with HMRC.
Guidance checked on . Dates and penalty amounts are HMRC's; your circumstances may differ. Gayle reviews this guide for accuracy quarterly, after any relevant announcement and for each new return cycle.
