If you’re filing a paper Self Assessment return, your deadline isn’t January. It’s 31 October, three months earlier than everyone filing online, and it’s easy to miss because most of the noise around Self Assessment is about January.
For the 2025/26 tax year, which ran from 6 April 2025 to 5 April 2026, a paper return has to reach HMRC by 31 October 2026. An online return, and any tax you owe, is due by 31 January 2027. Even if you’re filing online and 31 October doesn’t apply to you, the case for filing early is the same either way. Here’s what the paper deadline involves, what happens if it slips, how Making Tax Digital is closing the paper route, and why the earlier you file, the better your position.
The date that counts is the date HMRC receives it
For a paper return, what matters is when HMRC receives it, not when you post it. If HMRC has no record of receiving your return by 31 October, the late filing penalty is issued automatically. Post it well ahead of the deadline and get proof of postage, so that if something goes astray you can show when it was sent. This year 31 October falls on a Saturday, so don’t rely on a weekend delivery. Aim to have it with HMRC by Friday 30 October.
If your notice to file arrives late
The 31 October date applies where HMRC issued your notice to file on or before 31 July. If you’re new to Self Assessment, or the notice reached you later than that, the law moves the paper deadline. A notice issued after 31 July but on or before 31 October gives you three months from the date of the notice to file on paper, while the online deadline stays at 31 January. A notice issued after 31 October gives you three months from the notice date whichever way you file. Check the date on your notice before assuming 31 October is yours.
Why the paper deadline is earlier
When you file online, the software calculates your tax as you go, so there is nothing left to work out once the return reaches HMRC. On paper, you calculate the figure yourself, and HMRC has to check and process it once it arrives, which takes longer. That is the reason for the earlier cut-off. It gives them time to do that work before the crunch of online returns in January.
Why paper filing still exists
The two dates are written into law. Section 8 of the Taxes Management Act 1970 sets 31 October for a non-electronic return and 31 January for an electronic one, so the paper deadline stays until Parliament changes the legislation, whatever HMRC’s preference for digital.
Most people file online, but paper hasn’t disappeared. Some people prefer it, some can’t easily get online, and HMRC’s online service doesn’t cover every situation, so a small number of returns still have to go in on paper. If you’re one of them, have the return and the right supplementary pages in hand well before the deadline, because the three-month head start is easy to lose track of when October doesn’t feel urgent.
That is changing for the growing number of people brought into Making Tax Digital for Income Tax, which is covered in the next section.
How Making Tax Digital changes paper filing
Making Tax Digital for Income Tax replaces the annual return itself. If you’re brought into it, you keep digital records, send quarterly updates through compatible software, and finish the year with a final declaration that takes the place of the traditional Self Assessment return. The final declaration covers all of your income, not just the self-employment and property income that brought you into scope. It is still due by 31 January, and payment dates don’t change either: tax is still due on 31 January and 31 July.
There is no paper version of any of that. Unless you’re exempt, you can’t file your end-of-year return on paper, and the 31 October deadline stops applying to you.
When that happens depends on when you join. Those with qualifying income above £50,000 joined in April 2026, so the 2025/26 return, due on paper by 31 October 2026 or online by 31 January 2027, is the last traditional return they file. Their first final declaration, for 2026/27, is due by 31 January 2028. The same pattern follows for those over £30,000 from April 2027 and over £20,000 from April 2028: the return for the last tax year before you join is your last traditional one.
Some people are exempt. A few groups are exempt automatically, such as personal representatives completing a return for someone who has died, and others can apply if they’re digitally excluded, for example because of disability, age or a remote location. Exempt taxpayers carry on filing a traditional Self Assessment return, with the same 31 October and 31 January deadlines. Filing on paper out of preference doesn’t make you exempt, though. If you’ve always filed on paper because you like it, and you’re not digitally excluded, you’ll need to move to software when your turn comes.
Our earlier guide to Making Tax Digital sets out the thresholds and what the quarterly updates involve.
A second deadline: paying through your tax code
If you owe less than £3,000 and would like HMRC to collect it through your PAYE tax code, rather than as a single payment in January, your return has to be in by 31 October on paper, or by 30 December online. For 2025/26, the tax would then be collected through your 2027/28 tax code. That’s 30 December, not 31 December, and it’s a benefit of filing early that disappears if the return is left until January.
If the date slips
The penalty for a late return starts at £100, charged automatically even if you owe no tax. If the return is still outstanding three months later, a further £10 a day builds up for up to 90 days, a maximum of £900. At six months there is an additional penalty of 5% of the tax due or £300, whichever is greater, and the same again at twelve months. For a return a year overdue, that adds up to £1,600 in filing penalties before any late payment charges, and more where 5% of the tax due comes to more than £300, or where HMRC considers the delay deliberate.
Late payment is a separate matter. Tax paid late attracts a penalty of 5% of the unpaid amount at 30 days, another 5% at six months and another 5% at twelve months, plus interest.
Which return counts also matters. HMRC takes the first return it receives when working out late filing penalties. If you send in a paper return after 31 October, you can’t avoid the penalty by filing again online before 31 January. But if you planned to file on paper, missed 31 October, and file online instead by 31 January without sending the paper return, no late filing penalty applies. Treat that as a safety net rather than a strategy, but it’s useful to know if 31 October has already gone by.
If you have a reasonable excuse
Penalties can be cancelled where you have a reasonable excuse, and an appeal has to be made within 30 days of the penalty notice. Serious illness, the death of a close relative, a failure of HMRC’s website or your computer at a critical moment, and postal delays are the kind of circumstances generally accepted. Keep the evidence, including your proof of postage.
Why filing early beats filing on time, whichever deadline is yours
You know your bill months before it’s due. The tax itself isn’t due until 31 January either way, so filing early doesn’t move your payment date. It does mean you find out the number well in advance. That matters more than people expect, because the January payment can combine the balancing payment for 2025/26 with the first payment on account towards 2026/27, if payments on account apply to you, which is why the January bill is often bigger than people anticipate. Seeing that figure in October leaves time to set the money aside, rather than finding out in the last week of January.
Mistakes get caught with time to fix them. A return filed in October or November leaves months to notice something’s wrong, a missed source of income, a relief you’re entitled to but forgot to claim, before it’s locked in. A return filed on 30 January leaves almost no room for that.
You’re not in the January queue. Accountants and agents are busiest in the weeks before the January deadline, when every client is filing at once. A return submitted earlier gets more considered attention, simply because it isn’t one of several hundred landing in the same fortnight.
What to do now
Decide how you’re filing. Paper needs to reach HMRC by 31 October. Online has until 31 January, or 30 December if you want a bill under £3,000 collected through your tax code.
Check whether Making Tax Digital applies to you. If you’re in scope, this may be the last traditional return you file, and it’s the moment to get your software and records in place.
Gather your figures. Income from every source, allowable expenses, and anything you intend to claim relief on. A paper return needs the main return plus whichever supplementary pages apply to your income.
If it’s paper, have the return in hand, post early and keep proof. Receipt is what counts, not the postmark.
If you’d rather not do it yourself, talk to us now. The closer we get to 31 October, the tighter the timetable.
The real reason people leave it late
It’s rarely that people don’t know the deadline exists. Self Assessment feels like something to deal with once it’s urgent, and nothing about October or November creates that urgency the way late January does. Once the information is gathered, the return itself usually takes less time than people expect, and having it done early removes a job that would otherwise sit at the back of your mind for months.
Final Thought
A quote from our Principal, Sunil Aggarwal:
“Every January we watch the same pattern. The clients who filed in October are relaxed. The clients racing the deadline are not, and it’s almost never because their situation was more complicated.
The return doesn’t get easier by waiting. It just gets more stressful.”
Whether your deadline is 31 October or 31 January, the sooner it’s done, the sooner it stops being something you’re carrying around.
Get your Self Assessment return started with DRS and we’ll help you file early, with time to catch anything that needs catching.
- Email: info@drs-tax.com
- Telephone: 020 8059 1891
- Or submit an enquiry via our Contact Us page