Late filing vs late payment
These are two different penalty regimes. Filing late triggers fines even if you owe nothing. Here is the difference.
In one sentence
Late filing penalties are charged for submitting your tax return late, even if you owe nothing. Late payment penalties are charged separately for not paying your tax bill on time.
Quick answer
- Late filing penalty: £100 fixed fee from day one, regardless of whether you owe tax
- Late payment penalty: 5% of unpaid tax at 30 days, 6 months, and 12 months
- They can apply at the same time and add up quickly
- If you cannot pay, file on time anyway to avoid the filing penalty
Two different problems, two different penalty regimes
Many people assume that paying their tax bill late will automatically trigger a late filing penalty too. It will not. HMRC treats filing and paying as two separate obligations, and applies penalties separately for each.
That means you can be on time for one and late for the other, or late for both — and the penalties stack.
Side by side comparison
| Late filing | Late payment | |
|---|---|---|
| Triggered by | Submitting the return after 31 January | Not paying tax owed by 31 January |
| Initial penalty | £100 immediate, even if no tax owed | Daily interest from day one |
| After 30 days | Still £100 | 5% of unpaid tax |
| After 3 months | £10 per day, up to £900 | 5% surcharge still applies |
| After 6 months | 5% of tax due or £300, whichever is higher | Another 5% surcharge |
| After 12 months | Another 5% or £300 | Another 5% surcharge |
Worked example
Suppose you owe £4,000 in tax for the 2023/24 year, and you file and pay 6 months late.
- Late filing penalties: £100 + £900 (90 days × £10) + £300 = £1,300
- Late payment penalties: 5% of £4,000 at 30 days (£200) + 5% at 6 months (£200) = £400, plus interest
- Total extra cost: roughly £1,700 on top of the original £4,000
Filing on time but paying 6 months late would have cost only £400 plus interest. The lesson: file on time even if you cannot pay.
Action plan if you are running late
- If you cannot file or pay: file the return anyway, with your best estimate, to stop the late filing penalty.
- If you cannot pay: contact HMRC immediately to set up a Time to Pay arrangement.
- If you have a reasonable excuse (illness, bereavement, system outage): you can appeal one or both penalty types.
Key terms
- Late filing penalty
- Charged for submitting your Self Assessment return after the deadline. Starts at £100 even if you owe no tax.
- Late payment penalty
- Charged for not paying the tax owed by the deadline. 5% surcharges applied at 30 days, 6 months, and 12 months, plus daily interest.
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