Self Assessment Deadlines for Sole Traders: 31 January 2027
Sole traders must file a Self Assessment return each year and pay any tax due by the relevant deadlines. The filing deadline and the payment deadline are not the same thing — missing either carries a cost. Using this calculator throughout the year rather than only in January gives you time to build the reserve before the demand arrives.
Written and reviewed by James Whitfield · Last reviewed 3 November 2026 · Checked against 2026/27 HMRC rates · Editorial standards · Methodology
For the 2025/26 tax year, file your return online and pay the tax by 11:59pm on 31 January 2027.1 Paper returns were due by 31 October 2026. If you also have a job or pension and owe under £3,000, file online by 30 December 2026 to pay through your tax code.15 A second payment on account, if you make them, is due 31 July 2027.1 File a day late and it is £100, even with no tax to pay; pay late and it is 5% of the tax unpaid after 30 days, plus interest.2
- →31 October 2026: paper return for 2025/26 (passed).1
- →30 December 2026: online return if you want a bill under £3,000 collected through your tax code.15
- →31 January 2027: online return, 2025/26 balance and first 2026/27 payment on account.1
- →31 July 2027: second payment on account for 2026/27.1
- →5 October 2027: register if you started trading in 2026/27.3
Related: Deadlines for your first year · Your 2025/26 return: what's due 31 January 2027 · Can't pay by 31 January? · Self Assessment penalty calculator · Missed the 5 October deadline? · Pay through your tax code
- New sole traders must register by 5 October after the tax year they started trading.3
- Online return and any tax due: 31 January; second payment on account: 31 July.1
- File a day late and it is an automatic £100 penalty — even with no tax to pay.2
- Penalties escalate fast: £10 a day after three months, then 5% surcharges at six and twelve months.2
- You can appeal a penalty within 30 days if you have a reasonable excuse.2
Free check · 2026/27
Your own deadlines and amounts
See your 2026/27 bill, every payment with its date and amount, and what to set aside each month.
This winter: the 2025/26 return (due 31 January 2027)
The return you file this winter is for 2025/26 (6 April 2025 to 5 April 2026). The paper deadline was 31 October 2026. If you also have a job or pension, file online by 30 December 2026 and a bill under £3,000 can be collected through your tax code. Otherwise, file online and pay by 11:59pm on 31 January 2027.1
The 31 January 2027 payment is the balance of your 2025/26 bill plus the first payment on account for 2026/27; the second payment on account is due 31 July 2027. The penalties below apply to this return.
What filing late actually costs
The penalties for a late online return stack up on a fixed timetable, and the first one lands the day after 31 January whether or not you owe HMRC a penny. Here is what a return filed progressively later racks up.
| 1 day late | £100 fixed penalty |
| 3 months late | + £10 per day (max £900) |
| 6 months late | + 5% of tax due (or £300 if higher) |
| 12 months late | + a further 5% of tax due (or £300 if higher) |
Late payment is charged separately from late filing. Interest runs from 1 February on anything unpaid, and a 5% surcharge hits the outstanding tax at 30 days, six months and twelve months. The practical rule of thumb: even if you cannot pay, still file on time — that alone avoids the filing penalties, and you can then arrange a Time to Pay plan for the tax itself.
The key dates
5 October: register as self-employed with HMRC by this date if you became self-employed in the prior tax year and have not yet registered. Failure to register on time can result in penalties.
31 October: paper Self Assessment returns for the previous tax year must be filed by this date. Most sole traders file online and are not affected by the earlier paper deadline.
31 January: online Self Assessment returns for the previous tax year (ending 5 April) must be filed by this date. Any tax still outstanding for the prior year is also due on 31 January, along with the first payment on account for the current tax year.
31 July: second payment on account for the current tax year. This date has no associated filing requirement — it is a payment-only deadline.
Who must file a Self Assessment return
You must file a return if you are self-employed as a sole trader and your gross trading income (before expenses) exceeded £1,000 in the tax year. This covers freelancers, contractors, tradespeople, consultants and anyone else earning from self-employment.
Other common reasons to file include: untaxed income from property rental above the £1,000 property allowance; income from abroad; or HMRC specifically issuing you a notice to file. If HMRC sends you a notice, you must file even if you have nothing to declare.
If you stop being self-employed and have no other reason to file, you need to tell HMRC so they cancel your future filing obligation. Not filing when required will result in automatic penalties; continuing to receive filing notices while not submitting compounds the problem.
Late filing and late payment penalties
A £100 automatic penalty applies for a return filed even one day late, regardless of whether any tax is owed. After three months, an additional penalty of £10 per day applies (up to a maximum of £900). After six months, a further 5% surcharge (or £300, whichever is greater) is added. After twelve months, another 5% surcharge applies.
Late payment attracts interest from the day after the due date. After 30 days, a 5% late payment surcharge applies to the unpaid amount, with further 5% surcharges at six and twelve months.
If you have joined Making Tax Digital for Income Tax (compulsory from 6 April 2026 if your qualifying self-employment and property income is over £50,000), these penalties are replaced from the tax year you join: late returns earn penalty points, with a £200 penalty once you reach the threshold, and late payment costs 3% of tax unpaid at day 15 and another 3% at day 30 for 2026/27 (late payment penalties do not apply to payments on account, though interest does). Your 2025/26 return, due 31 January 2027, is still under the rules above.
If you are going to file late, do so as soon as possible — the penalties grow significantly with time. If you cannot pay the full amount, contacting HMRC before the deadline to arrange a Time to Pay agreement is considerably better than waiting.
Using the calculator before the deadline
A tax estimate has most value when it is used well before the payment date. Running the calculator in April or May — at the start of the new tax year — gives you twelve months to build the reserve. Running it again at mid-year lets you adjust if income has changed.
The monthly set-aside figure tells you what to move into a separate account each month. If you have been consistent with this throughout the year, January should not require emergency action.
The calculator also helps you assess whether your bill will exceed the £1,000 threshold for payments on account. If it does, the January demand includes both the prior year's balance and a payment on account for the current year — typically making it around 150% of the annual bill rather than the bill itself.
Frequently asked questions
When is the Self Assessment filing deadline?+
Online returns for the tax year ending 5 April must be filed by 31 January the following year. Paper returns have an earlier deadline of 31 October.
What is the penalty for filing late?+
An automatic £100 penalty applies from day one of being late, even if no tax is owed. Penalties increase significantly after three, six and twelve months of continued late filing. If you are in Making Tax Digital for Income Tax, a points-based regime (£200 at the threshold) replaces this from the tax year you join.
Can I pay my tax bill in instalments?+
HMRC offers Time to Pay arrangements for those who cannot pay in full by the deadline. Apply before the deadline rather than after — interest still applies but it avoids late payment surcharges in some cases.
Do I need to file if I have no tax to pay?+
Yes, if HMRC has issued you a notice to file. The £100 late filing penalty applies regardless of whether any tax is owed.
Can I appeal a late filing penalty?+
Yes. You have 30 days to appeal, and HMRC will cancel a penalty if you had a reasonable excuse — a serious illness, a bereavement, a fire or flood, or a genuine software or postal failure. 'I found it too difficult' or 'I didn't get a reminder' are not accepted. Appeal online or by post using form SA370, and file the outstanding return as soon as you can, because penalties keep accruing until it is in.
Sources & references
The rates, thresholds and rules in this guide are drawn from the official HMRC and GOV.UK sources below, using the confirmed 2026/27 figures. Each link opens the relevant official page in a new tab.
- Self Assessment tax returns: deadlines www.gov.uk/self-assessment-tax-returns/deadlines
- Self Assessment tax returns: penalties www.gov.uk/self-assessment-tax-returns/penalties
- Register for Self Assessment www.gov.uk/register-for-self-assessment
- Self Assessment tax returns www.gov.uk/self-assessment-tax-returns
- Pay your Self Assessment tax bill: through your tax code www.gov.uk/pay-self-assessment-tax-bill/through-your-tax-code
- HMRC interest rates for late and early payments www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates
Estimate your sole trader tax
The sole trader tax calculator turns this guidance into a concrete monthly take-home and tax reserve estimate, based on 2026/27 HMRC rates. Enter taxable profit — not turnover.