Two tax years are live at once right now. The 2025/26 return is the one you file this winter. The 2026/27 year is the one you are earning in — and if you are inside Making Tax Digital for Income Tax, it already has quarterly deadlines running.
Here is every date for both, in one place.
2025/26 tax year — the return you file now
The 2025/26 tax year ran from 6 April 2025 to 5 April 2026. These are its deadlines.
| Deadline | Date | Applies to |
|---|---|---|
| Register for Self Assessment | 5 October 2026 | Anyone who has not filed before, or who was registered but did not need to file for 2024/25 |
| Paper tax return | 31 October 2026 | Anyone filing on paper |
| File online to pay via your tax code | 30 December 2026 | Owe under £3,000 and already pay tax through PAYE |
| Online tax return | 31 January 2027 | Everyone filing online |
| Balancing payment + first payment on account | 31 January 2027 | All tax owed for 2025/26, plus the first instalment towards 2026/27 |
| Second payment on account | 31 July 2027 | Anyone making payments on account |
All deadlines are 11:59pm on the date shown.
2026/27 tax year — the year you are in
The 2026/27 tax year runs from 6 April 2026 to 5 April 2027. The pattern repeats exactly twelve months on.
| Deadline | Date |
|---|---|
| Register for Self Assessment | 5 October 2027 |
| Paper tax return | 31 October 2027 |
| File online to pay via your tax code | 30 December 2027 |
| Online tax return | 31 January 2028 |
| Balancing payment + first payment on account | 31 January 2028 |
| Second payment on account | 31 July 2028 |
You can file a 2026/27 return from 6 April 2027 onwards. Filing early does not bring the payment date forward — the tax is still due 31 January 2028.
MTD for Income Tax quarterly deadlines
Making Tax Digital for Income Tax is live. From 6 April 2026, sole traders and landlords with qualifying income over £50,000 (measured on their 2024/25 return) must keep digital records and send quarterly updates to HMRC.
| Quarterly update | Deadline |
|---|---|
| Quarter 1 | 7 August |
| Quarter 2 | 7 November |
| Quarter 3 | 7 February |
| Quarter 4 | 7 May |
Plus a year-end return, due by the usual 31 January.
The thresholds step down: over £30,000 of qualifying income (measured on 2025/26) brings you in from 6 April 2027, and over £20,000 (measured on 2026/27) from 6 April 2028. HMRC reviews your return each year and writes to people it identifies as being over the threshold — but do not wait for the letter. HMRC’s guidance is explicit that even if you do not receive one, you must still check your qualifying income yourself to find out whether you need to use the service, and make sure you are signed up in time.
Two points worth knowing. Quarterly updates are not five tax returns: they are summary submissions of income and expenses, without the reliefs, allowances and adjustments that go into a full return. And partnerships are not yet in scope — HMRC has published no timeline for them.
The dates people actually miss
5 October. This is a notification deadline, not a filing one, and it is the most commonly missed date in the calendar. If you started a side business in the 2025/26 tax year, or began letting a property, you must tell HMRC by 5 October 2026. Register late and HMRC gives you a filing deadline three months from the date of their letter or email — but the payment deadline does not move. Tax is still due 31 January 2027, and a “failure to notify” penalty may apply based on what is still unpaid at that date.
30 December. File online by this date and, if you owe less than £3,000 and already pay tax through PAYE, HMRC can collect it through next year’s tax code instead of demanding a lump sum on 31 January. It is a genuine cash flow win and almost nobody uses it. You cannot make a part payment to bring yourself under £3,000, and you cannot code out Class 2 National Insurance.
31 July. The second payment on account is the one that ambushes people who have already mentally closed the tax year. It is due whether or not you have filed anything since January.
31 October. Only relevant if you file on paper. Almost everyone files online, but trustees of registered pension schemes and non-resident companies must file on paper — and their deadline is 31 January, not 31 October.
What happens if you miss a deadline
Most taxpayers are still on the long-standing penalty regime:
| Lateness | Penalty |
|---|---|
| Immediately after the deadline | £100 — even if you owe no tax |
| 3 months late | £10 per day for up to 90 days (maximum £900) |
| 6 months late | 5% of the tax due or £300, whichever is greater |
| 12 months late | A further 5% or £300, whichever is greater |
Late payment is charged separately: 5% of the unpaid tax at 30 days, again at 6 months and again at 12 months, plus interest at 7.75%.
A points-based system now exists, but it is not universal. From 6 April 2026 it applies only to taxpayers mandated into MTD for Income Tax and to volunteers. It extends to everyone filing a personal Self Assessment return from April 2027. A lot of published guidance says “Self Assessment has moved to points” without that qualification. It has not — not yet, and not for most people.
For 2026/27 there is also a grace period: no penalty points for late quarterly updates. Digital records and quarterly updates are still legally required, and late return and payment penalties still bite.
Partnerships
A partnership files its own return, and each partner files a personal one. If the partnership return is late, every partner gets a penalty — not just the nominated partner who was supposed to file it.
One quirk: if your partnership’s accounting date falls between 1 February and 5 April and one of your partners is a limited company, the deadlines shift to 12 months from the accounting date for online returns and 9 months for paper.
Frequently asked questions
What is the Self Assessment deadline for 2025/26?
31 January 2027 for online returns and for paying any tax you owe. The paper deadline is 31 October 2026. If you have never filed before, you also need to register by 5 October 2026.
Can I file my tax return early?
Yes. You can file a 2025/26 return any time from 6 April 2026. Filing early does not move the payment deadline — the tax is still due 31 January 2027 — but it tells you what you owe with months to plan for it.
What happens if I register for Self Assessment after 5 October?
HMRC will give you a filing deadline three months from the date of their letter or email. The payment deadline does not change: tax is still due by 31 January. A failure to notify penalty may apply, calculated on the tax still unpaid at that date.
When are the MTD for Income Tax quarterly updates due?
7 August, 7 November, 7 February and 7 May, plus a year-end return. These apply to sole traders and landlords already mandated into MTD — currently those with qualifying income over £50,000.
Do I get a penalty if I file late but owe no tax?
Yes. The £100 late filing penalty applies even where there is no tax to pay. It is a filing penalty, not a tax-geared one.
Getting it filed on time
The deadlines are fixed and the penalties are automatic. What varies is how long it takes to pull the records together — and for anyone newly inside MTD for Income Tax, that is now a quarterly job rather than an annual one.
SmartFiling handles Self Assessment and MTD for Income Tax filing for a fixed fee, with a three-week turnaround from receiving your records. Everything is reviewed and signed off by an ICAEW Chartered Accountant, and it is all online — no appointments, no phone calls.
