If you missed the 31 January 2026 self-assessment deadline and haven't filed yet, HMRC started charging you £10 per day on 1 March. That's on top of the £100 automatic penalty you already owe.
As of today, 16 March, that's 16 days of daily penalties. Your total bill is £260 and climbing.
The penalty timeline
| When | What happens | Cumulative cost |
|---|---|---|
| 1 Feb 2026 | £100 automatic penalty | £100 |
| 1 Mar 2026 | Daily £10/day starts (up to 90 days) | £100 + £10/day |
| 31 May 2026 | Daily penalties cap at £900 | £1,000 |
| 1 Aug 2026 | 6-month: £300 or 5% of tax due | £1,300+ |
| 1 Feb 2027 | 12-month: another £300 or 5% | £1,600+ |
How to stop the clock today
- File immediately — even with estimated figures. HMRC allows you to submit approximate numbers and amend later. An estimated return stops the clock.
- File first, appeal second — if you have a reasonable excuse (serious illness, bereavement, HMRC service outage), you can appeal the penalties. But file NOW to stop them accumulating.
- Can't pay? Filing and paying are separate obligations. File to stop filing penalties. Then call HMRC's Payment Support Service (0300 200 3822) about a Time to Pay arrangement.
What counts as a reasonable excuse?
✅ HMRC will likely accept:
- Serious illness or hospital stay
- Bereavement of a close family member
- HMRC online service outage near the deadline
- Fire, flood, or theft of records
- Mental health condition preventing you managing affairs
❌ HMRC will reject:
- "I forgot"
- "I was too busy"
- "I didn't have the money" (you can file without paying)
- "I found it confusing"
The maths is brutal
- File today → save £10 tomorrow
- Wait a week → another £70
- Wait until daily penalties max out → £900 in daily penalties alone
There is no scenario where waiting helps.
I built a live penalty calculator that shows exactly what you owe right now, plus step-by-step appeal guides:
🔗 Self-assessment penalty calculator
🔗 Reasonable excuse guide + appeal template
🔗 Daily penalty breakdown with live counter
If you know a freelancer who's been putting off filing — send them this. Every day costs £10.
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