Self Assessment Deadline 31 January 2027: Key Dates for 2025/26
Self Assessment Deadline 31 January 2027: Key Dates for 2025/26
Short answer: the deadline for a 2025/26 Self Assessment tax return filed online is 11:59pm on 31 January 2027. Any tax you owe for the year is due by the same time. A paper return has to reach HMRC by 31 October 2026.
Self Assessment deadlines for 2025/26 at a glance
The 2025/26 tax year ran from 6 April 2025 to 5 April 2026. These are the dates that follow from it:
| Date | What is due |
|---|---|
| 6 April 2026 | First day you could send a 2025/26 return |
| 5 October 2026 | Tell HMRC you need to send a return, if you have never sent one or didn't need to last year |
| 31 October 2026 | Paper returns |
| 30 December 2026 | File online by now if you want the tax collected through your PAYE tax code |
| 31 January 2027 | Online returns, the tax you owe for 2025/26, and any first payment on account for 2026/27 |
| 31 July 2027 | Second payment on account, if you make them |
The dates are HMRC's: Self Assessment deadlines on GOV.UK.
Each deadline explained
5 October 2026: register for Self Assessment
If 2025/26 is the first year you need to send a return, you should have told HMRC by 5 October 2026. If you missed that date, register now. HMRC will write or email with your own filing deadline, which is 3 months from the date on that letter or email. The payment deadline doesn't move: tax is still due by 31 January 2027.
When you register online, your UTR usually appears in your HMRC account within 72 hours. By post it takes around 15 days. You need the UTR to file, so don't leave registering until January. See what you need to file through software.
31 October 2026: paper returns
A paper return has to reach HMRC by 11:59pm on 31 October 2026. That is three months before the online deadline. If you miss it, you can still file online by 31 January 2027 without a penalty.
If you live abroad, note that GOV.UK says non-residents can't use HMRC's own online service. Your choices are a paper return by 31 October, or software that supports the SA109, which gives you until 31 January.
30 December 2026: paying through your tax code
If you file online by 11:59pm on 30 December 2026, HMRC can collect what you owe through your PAYE tax code, spread over the following tax year, instead of you paying it in one go. GOV.UK says all of these must apply:
- you owe less than £3,000 on your tax bill
- you already pay tax through PAYE, for example as an employee or on a company pension
- you filed online by 30 December (or on paper by 31 October)
HMRC won't collect it this way if you don't have enough PAYE income, if you would pay more than half your PAYE income in tax, or if you would end up paying more than twice as much tax as you normally do. Paying through your tax code on GOV.UK.
31 January 2027: the main deadline
Two things are due by 11:59pm on 31 January 2027:
- your online tax return for 2025/26
- the tax you owe for 2025/26, plus the first payment on account for 2026/27 if you make them
Filing and paying are separate obligations with separate penalties. Filing on time doesn't protect you if you pay late, and paying on time doesn't protect you if you file late.
31 July 2027: second payment on account
Payments on account are advance payments towards your next bill. Each one is usually half of the tax you owed the previous year, and they are due on 31 January and 31 July. You don't have to make them if your last Self Assessment bill was less than £1,000, or if more than 80% of your tax was already collected outside Self Assessment, for example through your tax code. If you expect a lower bill next year, you can ask HMRC to reduce them. Payments on account on GOV.UK.
What happens if you miss the deadline?
Late filing penalties
| How late | Penalty |
|---|---|
| 1 day | £100, even if you have no tax to pay |
| 3 months | £10 a day, up to a maximum of £900 |
| 6 months | 5% of the tax due or £300, whichever is greater |
| 12 months | Another 5% of the tax due or £300, whichever is greater |
For example, a return filed 12 months late with £5,000 of tax due would attract £100 + £900 + £300 + £300 = £1,600 in filing penalties, before any penalties for paying late.
Late payment penalties and interest
| How late | Penalty |
|---|---|
| 30 days | 5% of the tax unpaid at that date |
| 6 months | 5% of the tax still unpaid |
| 12 months | 5% of the tax still unpaid |
HMRC also charges interest on tax paid late, at Bank Rate plus 4%. HMRC has a penalty estimator. If you have already missed a deadline, see how to file a late tax return: filing as soon as you can stops the penalties growing.
Can you get an extension?
No. The deadlines are fixed. The one exception is where HMRC told you to file late in the year: you then have 3 months from the date of its letter or email.
If you had a good reason for being late, you can appeal a penalty. GOV.UK says a reasonable excuse may include:
- your partner or another close relative died shortly before the deadline
- an unexpected stay in hospital, or a serious or life-threatening illness
- your computer or software failed while you were preparing your online return
- problems with HMRC's online services
- a fire, flood or theft that stopped you completing the return
- postal delays you could not have predicted
- delays related to a disability or mental illness
- you were unaware of, or misunderstood, your legal obligation
- you relied on someone else to send your return, and they did not
These will not count: your payment failed because you didn't have enough money, you found HMRC's online system too difficult, you didn't get a reminder, or you made a mistake on your return. Reasonable excuses on GOV.UK.
Who needs to send a tax return for 2025/26?
GOV.UK says you must send one if, in the tax year, you:
- were self-employed as a sole trader and earned more than £1,000 before expenses
- were a partner in a business partnership
- had to pay Capital Gains Tax
- had to pay the High Income Child Benefit Charge and don't pay it through PAYE
You may also need to send one if you had untaxed income, such as rent, tips and commission, savings interest, dividends or foreign income, or any taxable UK income as a non-resident. If HMRC has sent you a notice to file, you must file even if you owe nothing. Not sure? Check if you need to send a tax return on GOV.UK.
What to get ready
- Your UTR, and your Government Gateway user ID and password
- Your P60 and any P11D, if you were employed
- Income and expense records, if you were self-employed
- Rent received and property expenses, if you're a landlord
- Bank interest and dividend statements
- Details of anything you sold at a gain
File your 2025/26 return before the deadline
January is when most people file, and when HMRC's phone lines are busiest. Filing earlier tells you what you owe while there is still time to plan for it, and filing by 30 December may let you pay through your tax code.
- Create a free DTax Filer account and start your 2025/26 return.
- Enter your income. DTax Filer works out your tax as you go.
- Check the calculation, then submit to HMRC online.
See the plans and prices. If you find a mistake after filing, you can amend the return until 31 January 2028.
Frequently asked questions
When is the Self Assessment deadline for 2025/26?
11:59pm on 31 January 2027 for a return filed online, and 31 October 2026 for a paper return. Tax owed for 2025/26 is also due by 31 January 2027.
What happens if I miss the 31 January deadline?
You get a £100 penalty straight away, even if you owe no tax. From 3 months late HMRC adds £10 a day for up to 90 days, and there are further penalties of 5% of the tax due or £300, whichever is greater, at 6 and 12 months.
I missed the 5 October registration deadline. What now?
Register as soon as you can. HMRC will give you a filing deadline 3 months from the date of its letter or email. You still have to pay the tax you owe by 31 January 2027.
Do I still need to file if I have nothing to pay?
Yes, if HMRC has sent you a notice to file. The £100 late filing penalty applies even when the tax due is nil. If you think you no longer need to send a return, tell HMRC before the deadline.
Is the deadline for filing the same as the deadline for paying?
For an online return, yes: both are 31 January 2027. They are separate obligations, though, and each has its own penalties.
Can I pay my tax bill through my tax code?
Yes, if you owe less than £3,000, already pay tax through PAYE and file online by 30 December 2026. HMRC then collects it through your tax code over the following tax year.