by Asim Abbas
11 November 2026 
Self Assessment deadline 31 January 2027: what you must do and when
Self Assessment deadline 31 January 2027: what you must do and when
If you’re self-employed, a landlord, a company director or you have income outside PAYE, 31 January 2027 is the date HMRC holds you to for your 2025/26 tax return.
- File your 2025/26 return online by 11:59pm on 31 January 2027
- Pay any tax owed, plus your first payment on account for 2026/27, by the same date
- Late returns get an automatic £100 penalty, even with no tax to pay
- Owe less than £3,000? File by 30 December 2026 to pay through your tax code
Miss it and you’ll get an automatic £100 penalty, even if you don’t owe any tax. Leave it longer and the charges keep growing.
In this guide, you’ll find every key date for the 2025/26 tax year, what you need to pay and when, what happens if you’re late, and a simple plan to file with time to spare.
Which tax year does this deadline cover?
It covers the 2025/26 tax year, which ran from 6 April 2025 to 5 April 2026. Any income you received in that period that wasn’t fully taxed through PAYE goes on this return.
This year, 31 January falls on a Sunday. The deadline doesn’t move, because HMRC’s online service runs at weekends.
Key Self Assessment dates for 2025/26
Missed the registration date? Register now. You can still file on time once your UTR arrives. Check every date on HMRC’s Self Assessment deadlines page.
What you need to pay on 31 January
Your balancing payment
This is the tax you still owe for 2025/26 once any payments you’ve already made are taken off.
Your first payment on account
If your tax bill is more than £1,000, HMRC usually asks for advance payments towards next year’s bill, called payments on account. Each one is half of last year’s bill. You don’t make them if more than 80% of your tax is already collected at source, for example through PAYE.
Your 2025/26 bill is £4,000 and you made no payments on account. On 31 January 2027 you pay the £4,000 balancing payment plus a £2,000 first payment on account, so £6,000 in total. On 31 July 2027 you pay another £2,000.
Paying through your tax code
If you’re employed or get a pension and owe less than £3,000, HMRC can collect it through your tax code over the next tax year. You must file online by 30 December 2026 for this to happen.
Self Assessment tax calculator
Estimate your 2025/26 bill and payments on account in seconds.
What happens if you miss the deadline?
Late filing penalties
- 1 day late: £100 fixed penalty
- 3 months late: £10 a day for up to 90 days (a maximum of £900)
- 6 months late: a further 5% of the tax due or £300, whichever is higher
- 12 months late: another 5% or £300, and more if HMRC thinks you held back information on purpose
Late payment penalties and interest
Separate penalties apply if you pay late: 5% of the unpaid tax at 30 days, 6 months and 12 months. HMRC also charges interest from the day after the tax was due. Work out what you might owe with our late tax return penalty calculator or HMRC’s penalty estimator.
Can’t pay in full?
Don’t ignore it. If you owe £30,000 or less and have filed your return, you can usually set up a payment plan online, called Time to Pay. Find out more on GOV.UK.
The government has announced that late filing penalties will move to a points-based system for later tax years. For your 2025/26 return, the penalties above still apply.
Fixed-fee accountancy support
Transparent monthly packages for sole traders, landlords and limited companies. Fixed fees agreed upfront, VAT included.
Get a fixed-fee quoteCall 0161 531 4179Does Making Tax Digital change this deadline?
Not for your 2025/26 return. You file it the usual way by 31 January 2027.
If your income from self-employment and property was over £50,000, you’ve been in Making Tax Digital for Income Tax since 6 April 2026. You send quarterly updates through software, and your 2026/27 return will be due by 31 January 2028.
From April 2027 the threshold drops to £30,000, based on the income in the return you’re filing now. So this return also tells you whether you’re next.
What should I do next?
Use HMRC’s tax return checker and make sure you have your UTR and login.
P60 or P45, invoices, expenses, rent statements, bank interest, dividends, pension contributions and any assets you sold.
Use our free tax calculators and set the money aside now.
Filing early gives you time to fix login problems or missing paperwork.
Bank transfers can take up to three working days. Use your 10-digit UTR followed by K as the reference.
Our Self Assessment service handles everything, and our late tax returns team helps if you’re behind.
Frequently Asked Questions
What time is the deadline on 31 January 2027?
Your online return must reach HMRC by 11:59pm on 31 January 2027, and your tax must be paid by the same time. The paper deadline of 31 October 2026 has passed, so you now need to file online.
Does the deadline move because 31 January 2027 is a Sunday?
No. HMRC’s online service runs at weekends, so the deadline stays at 11:59pm on Sunday 31 January. Bank transfers can take longer over a weekend, so pay a few days early.
Will I get a penalty if I don’t owe any tax?
Yes. The £100 late filing penalty applies even if you owe nothing or are due a refund. If you no longer need to file, ask HMRC to cancel the return request before the deadline.
Can I reduce my payments on account?
Yes, if you expect your income to fall. You can reduce them in your HMRC online account or on form SA303. If you reduce them too far, HMRC charges interest on the shortfall.
I registered late. Can I still file on time?
Usually, yes. Register straight away, because your Unique Taxpayer Reference (UTR) can take a couple of weeks to arrive. Once you have it, you can file online before 31 January.
How much does it cost to have an accountant file my return?
At Wingate, a straightforward Self Assessment return starts from £150 including VAT, and £250 if you’re self-employed, a landlord or have several income sources. The fee is fixed and agreed before we start.
Need help with this? Wingate Accountants offers fixed-fee online accountancy support across the UK. Call 0161 531 4179 or request a quote at wingateaccountants.co.uk.
About the Author
Ali Imran
I’m Ali Imran, an accountant at Wingate Accountants. I help sole traders, landlords and directors get their returns filed early and accurately, without the last-minute panic.
