Self Assessment Penalty Calculator 2025/26
What HMRC charges if your 2025/26 tax return or bill is late: the £100 fine, daily penalties, 5% penalties and interest, from the 31 January 2027 deadline.
Rates checked against GOV.UK on 19 October 2026 · How we check our calculators
Your 2025/26 return and bill
What HMRC would charge
Penalties
£350.00
Interest
£94.49
89 days at 7.75%
Late filing
- Return filed late (1 February 2027)
- £100.00
Late payment
- 30 days late: 5% of the unpaid tax (3 March 2027)
- £250.00
Total on top of your tax£444.49
When each penalty starts
For a 2025/26 return filed online, with the return and the balance both due by 31 January 2027.
| From | Late filing | Late payment |
|---|---|---|
| 1 February 2027 | £100 | Interest on anything unpaid, counted from 31 January |
| 3 March 2027 | - | 5% of the tax still unpaid at the end of 2 March |
| 1 May 2027 to 29 July 2027 | £10 a day, up to £900 | - |
| 1 August 2027 | 5% of the tax on the return, or £300 if more | - |
| 3 August 2027 | - | Another 5% if still unpaid at the end of 2 August |
| 1 February 2028 | Another 5% or £300 (more if information was deliberately withheld) | - |
| 3 February 2028 | - | Another 5% if still unpaid at the end of 2 February |
Interest is 7.75% a year (Bank of England base rate plus 4%, from 9 January 2026) and changes when the base rate does. The Making Tax Digital penalty points don't apply to 2025/26 returns.
Can't pay by 31 January? Set up a payment plan
File your return on time anyway: the late filing penalties are separate, and apply even if you can't pay. Then set up a payment plan, which HMRC calls Time to Pay, to pay the overdue tax in monthly instalments by Direct Debit.
Do it before 3 March 2027. The first 5% late payment penalty is charged on tax still unpaid at the end of 2 March. While an agreed plan is kept to, HMRC doesn't charge late payment penalties on that tax. It still charges interest, so paying faster costs less.
- You can check if you're eligible and set the plan up online. You'll need your Unique Taxpayer Reference, your bank details and details of your income and spending.
- HMRC usually asks for around half of what's left each month after rent, food, bills and other fixed costs.
- There's no fixed time limit: it depends on how much you owe and what you can afford.
- If you can't set it up online, contact HMRC. If you have savings or assets, HMRC will expect you to use them first.
If your bill isn't overdue yet, a Budget Payment Plan lets you pay weekly or monthly by Direct Debit towards your next bill, as long as you're up to date with the last one. To see what's coming, use the payments on account calculator.
Sources: GOV.UK, "If you cannot pay your tax bill on time" and "Pay your Self Assessment tax bill"; HMRC manual SALF308A on suspending late payment penalties.
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Important Disclaimer
This tool provides indicative calculations only and does not constitute financial, accounting, tax, or legal advice. The accuracy of results depends on the accuracy of information you provide. Consult a qualified professional for complex situations.
Overview
Missing the 31 January 2027 deadline for your 2025/26 Self Assessment can cost you in two separate ways. Filing late brings fixed penalties: £100 straight away, then daily penalties and percentage penalties the longer the return is outstanding. Paying late brings interest from 31 January plus three 5% penalties if the tax is still unpaid at set dates. The two run independently, so filing on time saves the filing penalties even if you can't pay. This calculator works out both from the dates you file and pay, using the rules in Schedules 55 and 56 to the Finance Act 2009 as HMRC's own manuals apply them, and the late payment interest rate on GOV.UK.
Worked Example (2026/27)
Worked Example: Filed in March, Paid in April
Scenario: a 2025/26 bill of £5,000, none of it paid by 31 January 2027. The return goes in on 15 March 2027 and the tax is paid on 30 April 2027.
Late filing: - Filed after 31 January: £100 - Filed before 1 May, so no daily penalties
Late payment: - Still unpaid at the end of 2 March 2027: 5% × £5,000 = £250 - Interest from 31 January to 30 April (89 days): £5,000 × 7.75% × 89 ÷ 365 = £94.49
Total on top of the tax: £444.49
If instead the return was filed on time and the tax paid on 31 July 2027, there's no filing penalty, but the 5% (£250) and 181 days of interest (£192.16) still apply. With a payment plan agreed by 2 March 2027 and kept to, only the interest is charged.
2026/27 Rates & Thresholds
| From | Late filing (online return) | Late payment |
|---|---|---|
| 1 February 2027 | £100 | Interest on unpaid tax, counted from 31 January |
| 3 March 2027 | 5% of the tax still unpaid at the end of 2 March | |
| 1 May to 29 July 2027 | £10 a day, up to £900 | |
| 1 August 2027 | 5% of the tax on the return, or £300 if more | |
| 3 August 2027 | Another 5% of what's still unpaid | |
| 1 February 2028 | Another 5% or £300 (more if information was deliberately withheld) | |
| 3 February 2028 | Another 5% of what's still unpaid | |
| Interest rate | 7.75% a year since 9 January 2026 (base rate + 4%) |
Can't Pay? Set Up a Time to Pay Plan Before 3 March
If you can't pay in full, HMRC can agree a payment plan, which it calls Time to Pay, so you pay the overdue tax in monthly instalments by Direct Debit. HMRC usually asks for around half of what you have left each month after rent, food, bills and fixed costs, and there's no fixed time limit.
Timing matters. While an agreed plan is kept to, HMRC doesn't charge late payment penalties on that tax (Schedule 56 paragraph 10, HMRC manual SALF308A). The first 5% is charged on tax still unpaid at the end of 2 March 2027, so agree the plan before then. Interest still runs throughout, so paying faster costs less overall.
You can check if you're eligible and set the plan up online with your Unique Taxpayer Reference, bank details and details of your income and spending. If you can't, contact HMRC.
The Making Tax Digital Penalties Don't Apply Yet
Making Tax Digital for Income Tax brings a points-based system for late returns and different late payment penalties. GOV.UK is clear that these apply from the tax year you join, and that current penalties still apply to the 2025 to 2026 return due 31 January 2027, even if you joined Making Tax Digital in April 2026. For the new system, see our guide to MTD penalties.
Reasonable Excuse and Appeals
HMRC can cancel a late filing or late payment penalty if you had a reasonable excuse and put things right without unreasonable delay once it ended. Not having enough money isn't usually accepted on its own. You can appeal a penalty you think is wrong, and a late payment penalty doesn't have to be paid until the appeal is decided. A penalty that is due and not paid within 30 days of HMRC's notice is charged interest.
Common Mistakes HMRC Penalises
- Not filing because you can't pay. The filing penalties are separate, and £100 is charged the day after the deadline either way.
- Waiting until after 2 March 2027 to ask for a payment plan, when the first 5% late payment penalty has already been charged.
- Assuming there's no penalty if no tax is due. The £100 and the daily penalties still apply.
- Paying by Bacs on 31 January 2027. It's a Sunday, so a Bacs payment has to reach HMRC by Friday 29 January.
- Expecting the Making Tax Digital points system to apply to the 2025/26 return. It doesn't.
When to Seek Professional Advice
Speak to an accountant or contact HMRC early if you owe tax for more than one year, you have other tax debts, you think you have a reasonable excuse, or HMRC has charged you a penalty for deliberately withholding information. This calculator covers an online 2025/26 return. Paper returns had an earlier deadline (31 October 2026), and partnerships, trusts and amended returns follow different dates.
Frequently Asked Questions
What is the penalty for filing my 2025/26 tax return late?+
£100 if the online return isn't filed by 31 January 2027. If it's still not filed 3 months later, £10 a day for up to 90 days from 1 May 2027, so up to £900. At 6 months (1 August 2027) there's a further penalty of 5% of the tax on the return or £300, whichever is more, and the same again at 12 months (1 February 2028).
What is the penalty for paying my Self Assessment bill late?+
HMRC charges interest on unpaid tax from 31 January 2027, at 7.75% a year since 9 January 2026. On top of that, 5% of the 2025/26 tax still unpaid at the end of 2 March 2027, another 5% of what's unpaid at the end of 2 August 2027, and another 5% at the end of 2 February 2028.
I can't pay my tax bill by 31 January 2027. What should I do?+
File your return on time anyway, because the late filing penalties are separate. Then set up a payment plan (Time to Pay) to pay the overdue tax in monthly instalments by Direct Debit. If HMRC agrees the plan by 2 March 2027 and you keep to it, you won't be charged late payment penalties on that tax, but interest still runs. You can check if you're eligible and set it up online, or contact HMRC.
How much will HMRC ask me to pay each month on a payment plan?+
HMRC looks at what you have left each month after rent, food, utility bills and other fixed costs, and usually asks for around half of it. There's no fixed time limit on the plan. If you have savings or assets, HMRC expects you to use them to reduce the debt first.
Do I get a penalty for filing late if I don't owe any tax?+
Yes. The £100 penalty and the daily penalties don't depend on the tax due, and the 6 and 12 month penalties are at least £300 each even when 5% of the tax would be less.
Do the new Making Tax Digital penalty points apply to my 2025/26 return?+
No. GOV.UK says the current penalties still apply to the 2025 to 2026 return due 31 January 2027, even if you started using Making Tax Digital for Income Tax from 6 April 2026. The new points and late payment penalties apply from the tax year you join.
Are late payment penalties charged on payments on account?+
Not directly. A late payment on account is charged interest from its due date. The 5% penalties are worked out on the year's tax left unpaid 30 days after that year's balancing payment date, so a 2026/27 payment on account still unpaid at the end of 2 March 2028 would count.
Can I appeal a Self Assessment penalty?+
Yes. HMRC can cancel a penalty if you had a reasonable excuse, such as a serious illness or a failure of HMRC's systems, and you put things right without delay once the excuse ended. Not having enough money usually isn't accepted on its own. HMRC also charges interest on a penalty that isn't paid within 30 days of the notice.
Sources and how this calculator is checked
The rates and thresholds in this calculator come from the GOV.UK pages below. We last checked them on . The calculation engine is covered by 400+ automated tests, whose expected figures come from GOV.UK worked examples and PolicyEngine UK, an open-source model of the UK tax system. Read our methodology.
- Self Assessment tax returns: penalties (gov.uk)
- HMRC manual SALF208A: penalties for filing a tax return late (gov.uk)
- HMRC manual SALF308A: late payment penalties on unpaid Income Tax (gov.uk)
- HMRC interest rates for late and early payments (gov.uk)
- Penalties for Making Tax Digital for Income Tax (which years they apply to) (gov.uk)
- If you cannot pay your tax bill on time: setting up a payment plan (gov.uk)
Spotted a figure that doesn't match GOV.UK? Tell us and we'll correct it.
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