Self Assessment late penalty calculator
The 2025-26 online return and payment are due by 31 January 2027. Enter what you owe and how late you are to estimate the penalties.
No penalty: file and pay by 31 January.
Key dates
| What | Deadline |
|---|---|
| Register for Self Assessment (new this year) | 5 October 2026 |
| Paper return for 2025-26 | 31 October 2026 |
| Online return for HMRC to collect via PAYE code (under £3,000 owed) | 30 December 2026 |
| Online return and payment for 2025-26 | 31 January 2027 |
| Second payment on account | 31 July 2027 |
How the penalties work
- 1 day late: £100 fixed penalty.
- After 3 months: £10 a day, up to £900.
- After 6 months: 5% of the tax due or £300, whichever is higher.
- After 12 months: another 5% or £300, whichever is higher.
- Paying late: 5% of the unpaid tax at 30 days, 6 months and 12 months, plus interest.
Questions
Do I pay the £100 if I owe no tax?
Yes. The late filing penalty applies even when no tax is due or the tax is paid on time.
Is interest charged as well?
Yes. HMRC charges late payment interest on top of penalties, at Bank Rate plus 4%. Check GOV.UK for the current rate.
Can I appeal a penalty?
You can appeal if you had a reasonable excuse, such as serious illness or a bereavement. You usually have 30 days from the penalty notice.
Is this the same under Making Tax Digital?
No. People in Making Tax Digital for Income Tax move to a points-based late submission regime. This calculator covers the standard regime.
An estimate, not tax advice. HMRC's own figures are final. Official rules and estimator: GOV.UK.