Written for the 2025/26 tax year, the return due by 31 January 2027. Checked against GOV.UK on 6 October 2026.
HMRC must receive a paper Self Assessment tax return for the 2025/26 tax year by 11:59pm on 31 October 2026, or you’ll get a late filing penalty. The deadline for an online tax return is three months later: 11:59pm on 31 January 2027. This guide sets out both deadlines, who still has to use paper and what an accountant can do from here. It comes from Wainwrights Accountants in Bromborough, Wirral. We work with clients across the UK.
Key dates for the 2025/26 tax return
| What | Date or figure | Source |
|---|---|---|
| Paper tax return | HMRC must receive it by 11:59pm on 31 October 2026 | GOV.UK: Self Assessment deadlines |
| Online tax return | 11:59pm on 31 January 2027 | GOV.UK: Self Assessment deadlines |
| Online return, to pay through your tax code | 11:59pm on 30 December 2026 | GOV.UK: Self Assessment deadlines |
| Pay the tax you owe | 11:59pm on 31 January 2027 | GOV.UK: Self Assessment deadlines |
| Initial penalty for a late return | £100 | GOV.UK: Self Assessment penalties |
When is the paper tax return deadline for 2025/26?
11:59pm on 31 October 2026. GOV.UK says HMRC must receive your paper tax return by then or you’ll get a late filing penalty. The test is when HMRC receives it, not when you post it. You could send it any time on or after 6 April 2026.
The paper form is the SA100. GOV.UK says you can download it, or call HMRC and ask for one.
What happens if you miss 31 October?
A paper return that reaches HMRC after 31 October 2026 gets a late filing penalty. GOV.UK sets the penalties out as:
- an initial £100 penalty
- after 3 months, additional daily penalties of £10 per day, up to a maximum of £900
- after 6 months, a further penalty of 5% of the tax due or £300, whichever is greater
- after 12 months, another 5% or £300 charge, whichever is greater
The online deadline is separate, and later. GOV.UK says you must submit your online tax return by 11:59pm on 31 January 2027 or you’ll get a late filing penalty. The two deadlines are set separately, one for paper returns and one for online returns. So if you have not sent a paper return, you can file online instead, and the deadline for an online return is 11:59pm on 31 January 2027.
Can you file online instead of on paper?
Most people can. GOV.UK says you can file online if you are self-employed, or if you are not self-employed but still send a tax return, for example because you get income from renting out a property. You need sign in details and your Unique Taxpayer Reference (UTR). If you’re filing for the first time, you must register for Self Assessment before using the service.
HMRC’s own online service does not take every return. GOV.UK says you cannot use it for a partnership, for a trust or an estate, if you lived abroad as a non-resident, to report multiple chargeable event gains, or if you get income from a trust, are a Lloyd’s underwriter or are a religious minister. For those it says to use commercial software, or to download or request other forms.
Who has a different paper deadline?
Two groups, according to GOV.UK.
- Trustees of a registered pension scheme and non-resident companies cannot send a return online. HMRC must receive their paper tax return by 31 January 2027.
- Partnerships with a limited company as a partner, where the partnership’s accounting date is between 1 February and 5 April. Their deadline is 12 months from the accounting date for an online return and 9 months for a paper return.
Does the deadline change how you can pay?
It can. GOV.UK says you can pay your Self Assessment bill through your PAYE tax code if you owe less than £3,000, you already pay tax through PAYE, and you submitted your paper tax return by 31 October or your online tax return by 30 December. For the 2025/26 return, the online date is 11:59pm on 30 December 2026. If you miss it, you have to pay another way.
However you file, the tax you owe is due by 11:59pm on 31 January 2027.
Can an accountant file your return online for you?
Yes. We prepare your Self Assessment tax return from your records and file it online with HMRC, which makes 31 January 2027 the date to work to.
Starting sooner helps. GOV.UK says sending a return earlier means you find out what you owe, can budget, and have time to pay your bill by 31 January.
A personal tax return with us is from £20 a month + VAT (£24 including VAT). Prices are indicative: our team confirms the scope and final price. To hand yours over, get a quote or book a free call.
What do people ask about the paper tax return deadline?
Is the paper tax return deadline the date I post it?
No. GOV.UK says HMRC must receive your paper tax return by 11:59pm on 31 October 2026.
I missed the paper deadline. Can I file online instead?
In most cases, yes, if you have not already sent a paper return. The deadline for an online return is 11:59pm on 31 January 2027. GOV.UK says you can file online if you are self-employed or send a tax return for another reason, such as rental income. HMRC’s own online service does not take some returns, such as partnership and trust returns, which need commercial software.
What is the penalty for a late paper tax return?
An initial £100 penalty, then daily penalties of £10 per day after 3 months, up to a maximum of £900, with further penalties after 6 months and 12 months.
Where do I get a paper tax return form?
GOV.UK says you can download the SA100 tax return form, or call HMRC and ask for one.
Can Wainwrights file my return if I’ve always used paper?
Yes. We prepare your Self Assessment tax return from your records and file it online with HMRC. Get a quote or book a free call to start.
Deadlines and penalties change from one tax year to the next, and how they apply depends on your own circumstances. This guide is general information, not personal advice. To talk yours through with an accountant in Bromborough, get a quote or book a free call.