Self Assessment Deadline 31 January 2027: A Checklist for UK Sole Traders
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If you are a sole trader, the online Self Assessment tax return for the 2025/26 tax year (6 April 2025 to 5 April 2026) is due by 11:59pm on 31 January 2027. The same day is also the deadline for paying what you owe. Here are the dates, the penalties, the records to gather and a step-by-step checklist. Every date and figure has been checked against GOV.UK.
The 2025/26 Self Assessment deadlines at a glance
| What | Deadline |
|---|---|
| Tell HMRC you need to file (register for Self Assessment) if you have not sent a return before, or did not need to send one for 2024/25 | 5 October 2026 |
| Paper tax return | 11:59pm on 31 October 2026 |
| Online return if you want an amount you owe collected through your tax code | 11:59pm on 30 December 2026 |
| Online tax return | 11:59pm on 31 January 2027 |
| Pay your balancing payment for 2025/26 and your first payment on account for 2026/27 | 31 January 2027 |
| Second payment on account for 2026/27 | 31 July 2027 |
The registration and paper deadlines have now passed. If you registered after 5 October 2026, HMRC will send you a letter or email giving you a different deadline to send your return, which will be 3 months from the date on that letter or email. You must still pay the tax you owe by 11:59pm on 31 January 2027. If you missed the paper deadline, you can still file online by 31 January 2027.
What you pay on 31 January 2027
The January bill is often bigger than one year's tax because of payments on account: advance payments towards your next tax bill, including Class 4 National Insurance if you are self-employed. Each one is usually half of the tax you owed for the previous year, and they are due by 31 January and 31 July.
On 31 January 2027 you may need to pay:
- your balancing payment for 2025/26: the tax you owe for the year, minus any payments on account you have already made towards it
- your first payment on account for 2026/27
You do not have to make payments on account if the tax you owed last year was less than £1,000, or if you paid more than 80% of the tax you owed outside Self Assessment (for example through your tax code).
GOV.UK gives an example for someone filing for the first time with a £3,000 bill: they pay £4,500 by the January deadline (the £3,000 bill plus a £1,500 first payment on account), then a second payment on account of £1,500 the following 31 July. If you know your next bill will be lower, you can ask HMRC to reduce your payments on account, online or with form SA303, but you will be charged interest on the difference if your bill turns out higher.
31 January 2027 is a Sunday
If a payment deadline falls on a weekend or bank holiday, your payment needs to reach HMRC on the last working day before, which is Friday 29 January 2027, unless you pay by Faster Payments or by debit or credit card. Bacs and an existing Direct Debit take 3 working days; a new Direct Debit takes 5. You can no longer pay at the Post Office.
Penalties and interest if you are late
Late filing
- an initial £100 penalty
- after 3 months, £10 a day, up to a maximum of £900
- after 6 months, a further 5% of the tax due or £300, whichever is greater
- after 12 months, another 5% or £300, whichever is greater
Late payment
You get a penalty of 5% of the tax unpaid at 30 days, at 6 months and at 12 months. HMRC also charges interest on the amount owed. Late payment interest is set at the Bank of England base rate plus 4%, and HMRC lists it as 7.75% from 9 January 2026. The rate follows the base rate, so check GOV.UK for the current figure.
If you registered after 5 October and do not pay all of your tax bill by 31 January, you may also get a ‘failure to notify’ penalty, based on the amount still left to pay. If you have a reasonable excuse, you can appeal against a penalty. If you cannot pay in full, you may be able to set up a payment plan with HMRC, who will check whether it is affordable for you.
What records to gather
You do not send your records to HMRC with your return, but you need them to work out your profit or loss and to show HMRC if asked. For 2025/26, pull together:
- Sales and income: sales invoices, till rolls, receipts and bank slips
- Business expenses: receipts for goods, stock and anything else you bought for the business
- Bank statements for any account you use for the business
- Mileage: your log of business journeys, if you use simplified mileage rates (see our mileage log book guide)
- Personal income records, such as other income you need to declare
- VAT records if you are VAT registered, and PAYE records if you employ people
If you use traditional (accruals) accounting rather than cash basis, you will also need what you are owed, bills you have received but not paid, stock and work in progress at the year end, year-end bank balances, money you put into the business and money you took out for your own use.
Keep your records for at least 5 years after the 31 January submission deadline. For a 2025/26 return due by 31 January 2027, that means until at least the end of January 2032.
Step-by-step checklist
- Check you are registered. If this is your first return and you registered late, look for HMRC's letter or email with your filing deadline.
- Sign in to your HMRC online account early, so any access problems are sorted before January.
- Gather your records for 6 April 2025 to 5 April 2026 using the list above.
- Total your income and allowable expenses month by month, then for the year, to work out your profit.
- Check your payments on account: in your online account, view your latest return and select ‘View statements’ to see what you have paid and what is due.
- Estimate your bill so you know roughly what to pay on 31 January, including the first payment on account for 2026/27.
- Submit your online return, ideally well before 31 January 2027 (or by 30 December 2026 if you want an amount collected through your tax code).
- Pay in time: allow for 31 January 2027 being a Sunday and for how long your payment method takes.
- Diary 31 July 2027 for your second payment on account, and start putting money aside for it now.
- Set up your records for the next year so the 2026/27 return is easier.
Is Making Tax Digital relevant?
Making Tax Digital (MTD) for Income Tax applies to sole traders and landlords registered for Self Assessment, based on their qualifying income from self-employment and property. If your qualifying income was over £50,000 in 2024/25, you should have started using MTD from 6 April 2026. If it is over £30,000 in 2025/26, the year you are filing for now, you will need to use it from 6 April 2027. If it is over £20,000 in 2026/27, you will need to use it from 6 April 2028. HMRC writes to you if your return shows you are over the threshold, but it is still your responsibility to check. You still need to send a Self Assessment return for the tax year before you start MTD, so the 31 January 2027 return is due as normal. Use HMRC's checker on GOV.UK to see whether and when MTD applies to you, and whether you might be exempt.
For more on what to keep and the dates ahead, read self-employed record keeping for 2027/28.
This guide is general information, not tax advice. Sources: GOV.UK pages on Self Assessment deadlines, penalties, payments on account, paying your bill, HMRC interest rates, business records and Making Tax Digital for Income Tax, checked on 4 November 2026. Rules can change. Check gov.uk or speak to an accountant about your own situation.