Self Assessment Late Penalty Calculator for the 2025/26 Return
Miss the 31 January 2027 online deadline for your 2025/26 return and HMRC charges £100, even if you owe nothing 1. After 3 months it can add £10 a day for up to 90 days, then 5% of the tax due or £300 (whichever is more) at 6 months and again at 12 months 1. Paying late is charged separately: 5% of the unpaid tax at 30 days, 6 months and 12 months 1, plus interest, currently 7.75% a year 4. Enter your figures below for the total.
The dates that trigger each penalty on the 2025/26 return
| If... | Penalty |
|---|---|
| The return is filed after 31 January 2027 | £100 1 |
| It is still not filed on 1 May 2027 | £10 a day, up to 90 days (£900) 2 |
| It is still not filed on 1 August 2027 | 5% of the tax due or £300, whichever is more 1 |
| It is still not filed on 1 February 2028 | Another 5% or £300; it can be higher if information was deliberately withheld 2 |
| Tax is still unpaid after 2 March 2027 (30 days) | 5% of the unpaid tax 3 |
| Tax is still unpaid after 2 August 2027 | A further 5% of what is unpaid 3 |
| Tax is still unpaid after 2 February 2028 | A further 5% of what is unpaid 3 |
| Any tax paid after 31 January 2027 | Interest from 1 February 2027 until it is paid 4 |
Filing and paying are separate. File on time and pay late, and you only face the payment penalties and interest. Pay on time and file late, and you only face the filing penalties. The legislation charges the late payment penalties on the tax due under section 59B of the Taxes Management Act 1970, the final payment for the year 3; a late payment on account is charged interest.
What filing and paying late costs on a £2,000 bill
| When | Filing penalties | Payment penalties | Interest | Total |
|---|---|---|---|---|
| Filed and paid 14 February 2027 | £100 | £0 | £5.95 | £105.95 |
| Filed on time, paid 15 March 2027 | £0 | £100 | £18.26 | £118.26 |
| Filed and paid 31 May 2027 | £410 | £100 | £50.96 | £560.96 |
| Filed and paid 31 August 2027 | £1,300 | £200 | £90.03 | £1,590.03 |
| Filed and paid 29 February 2028 | £1,600 | £300 | £167.32 | £2,067.32 |
Two weeks late costs £105.95, almost all of it the £100 filing penalty. Leave it until the end of May and the daily penalties have started. By the end of August the daily penalties have reached their £900 limit and the 6-month penalties have arrived.
If you are going to be late
- File anyway, even if you cannot pay. Filing stops the filing penalties growing. You can pay what you can and set up a payment plan: online if you owe £30,000 or less, are up to date with your returns, have no other tax debts and no other HMRC payment plans 9.
- Had a reasonable excuse? You can appeal a penalty 8. GOV.UK's examples include a close relative dying shortly before the deadline, an unexpected stay in hospital, or a serious illness 10.
- Making Tax Digital doesn't change this return. GOV.UK says the current penalties apply to the 2025/26 return due 31 January 2027 5.
Not sure what you owe? Work out the 2025/26 dividend tax with the past-years dividend tax calculator, then the January and July amounts with the payments on account calculator.
Frequently asked questions
What is the penalty for filing my 2025/26 tax return late?
£100 if the online return is not in by 31 January 2027, even if you owe nothing or pay on time. After 3 months HMRC can add £10 a day for up to 90 days (£900), and after 6 and 12 months a further 5% of the tax due or £300, whichever is more.
What is the penalty for paying late?
5% of the tax still unpaid 30 days after 31 January 2027, a further 5% of what is still unpaid at 6 months and another 5% at 12 months. Interest is charged on top from the day after the deadline.
Do I get a penalty if I file on time but cannot pay?
Not a filing penalty. Late payment penalties and interest still apply to anything unpaid. Filing on time and contacting HMRC about a payment plan keeps the cost down.
Do I pay a late filing penalty if I owe no tax?
Yes. The £100 fixed penalty applies even if there is no tax to pay or you have already paid it. The 6 and 12 month penalties are at least £300 each.
Is this the same as HMRC's own estimator?
It follows the same GOV.UK rules, with the dates for the 2025/26 return worked out from the legislation. HMRC's estimator on GOV.UK is the official one, and HMRC's own figures will be what you are charged.
Are the penalties changing under Making Tax Digital?
Not for this return. GOV.UK says the current penalties apply to the 2025/26 return due 31 January 2027; the new points-based penalties apply only from the year you join Making Tax Digital.
Sources & references
Every headline figure in this guide is drawn from the official HMRC and GOV.UK sources below and reflects the confirmed 2026/27 rates. Each link opens the relevant official page in a new tab.
- Self Assessment tax returns: penalties — GOV.UK ↗ https://www.gov.uk/self-assessment-tax-returns/penalties
- Finance Act 2009, Schedule 55: penalty for failure to make returns ↗ https://www.legislation.gov.uk/ukpga/2009/10/schedule/55
- Finance Act 2009, Schedule 56: penalty for failure to make payments on time ↗ https://www.legislation.gov.uk/ukpga/2009/10/schedule/56
- HMRC interest rates for late and early payments — GOV.UK ↗ https://www.gov.uk/government/publications/rates-and-allowances-hmrc-interest-rates-for-late-and-early-payments/rates-and-allowances-hmrc-interest-rates
- Penalties for Income Tax Self Assessment volunteers — GOV.UK ↗ https://www.gov.uk/guidance/penalties-for-income-tax-self-assessment-volunteers
- Self Assessment tax returns: deadlines ↗ https://www.gov.uk/self-assessment-tax-returns/deadlines
- Estimate your penalty for late Self Assessment tax returns and payments — GOV.UK ↗ https://www.gov.uk/estimate-self-assessment-penalties
- Disagree with a tax decision: appeal a penalty — GOV.UK ↗ https://www.gov.uk/tax-appeals/penalty
- If you cannot pay your tax bill on time: pay in instalments — GOV.UK ↗ https://www.gov.uk/difficulties-paying-hmrc/pay-in-instalments
- Tax appeals: reasonable excuses — GOV.UK ↗ https://www.gov.uk/tax-appeals/reasonable-excuses
Sources last checked: 3 November 2026.
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