Tax & compliance
When is the self assessment deadline?
By Kaiser Khan · Updated 17 July 2026
The main deadline
For the 2025/26 tax year (6 April 2025 to 5 April 2026), online self assessment returns and the balancing payment of any tax owed are due by midnight on 31 January 2027. Paper returns have an earlier deadline of 31 October 2026. Almost everyone now files online, so 31 January is the date that matters for most people.
Payments on account
If your previous tax bill was over £1,000 and less than 80% of your tax was collected at source, HMRC usually asks for payments on account: two advance payments towards the next year, due by 31 January and 31 July. Each is normally half of the previous year's bill. A balancing payment (or refund) then settles the year the following 31 January.
What happens if you miss it
An automatic £100 penalty applies the day after the deadline, even if you owe nothing. After three months, daily penalties of £10 can run up to £900; at six and twelve months, further charges of 5% of the tax due or £300 (whichever is greater) apply. Late payment adds interest and further percentage-based penalties.
Registering for the first time
If you have never filed before — for example, you started freelancing or became a landlord — you must tell HMRC by 5 October following the end of the tax year you first need to report. An accountant can handle registration, the return and the payments on account calculation in one engagement.
People also ask
What if I cannot pay my tax bill by 31 January?
File the return on time anyway — the £100 late-filing penalty is separate from late-payment charges. Then contact HMRC about a Time to Pay arrangement, which spreads the bill over instalments. Interest still applies, but penalties are smaller than ignoring the debt.
Do I still file if I owe no tax?
If HMRC has issued you a notice to file, you must submit a return even if nothing is owed — the £100 late-filing penalty applies regardless of the tax position. You can ask HMRC to withdraw the notice if you no longer meet the criteria.
Is the deadline the same every year?
The pattern is fixed: 31 January after the tax year ends for online filing and payment, 31 October after the tax year ends for paper returns. So for 2025/26 the online deadline is 31 January 2027.
This article is general information for UK businesses, not tax, legal, or financial advice, and thresholds change — confirm current rules on GOV.UK or with a qualified accountant before acting. Fee figures are indicative benchmarks from ourmethodology.