HMRC Penalty Calculator
See what a late return or late payment is actually costing, and how fast it grows from here.
What is being late already costing you?
HMRC penalties stack automatically — and part of them grows daily. See your number.
Includes the £100 fixed penalty, £10/day (days 91–180), 6- and 12-month surcharges, late-payment penalties and daily interest. Estimate, not a demand. We also appeal unfair penalties — it works more often than people think.
Late filing penalties are automatic and they compound. A Self Assessment return one day late costs £100 whether or not any tax is due. At three months, daily penalties of £10 begin and run for up to 90 days. At six and twelve months, further penalties are charged as a percentage of the tax owed. Interest runs on top of all of it, from the original due date.
How the charges stack
- £100 fixed penalty the day after the deadline — even if you owe nothing.
- £10 a day from three months late, capped at £900.
- At six months: 5% of the tax due, or £300 if greater.
- At twelve months: another 5% or £300, and more in serious cases.
- Late payment penalties and daily interest apply separately to the tax itself.
Reasonable excuse
HMRC can cancel penalties where something genuinely outside your control stopped you filing — serious illness, bereavement, a service failure at HMRC's end. It is not a catch-all, and "I forgot" or "my accountant was slow" will not carry it. Where a genuine excuse exists we make the case in the format HMRC expects, with evidence attached.
If you cannot pay
Filing and paying are separate obligations, and the worst outcome is skipping both. File the return even if the money is not there: it stops the filing penalties immediately, and opens the door to a Time to Pay arrangement that spreads the tax over instalments instead of leaving it to grow.
Penalty questions
I owe no tax. Do I still get a penalty?
Yes. The £100 filing penalty applies regardless of whether tax is due — it is charged for the missing return, not the missing money.
Can penalties be cancelled?
Sometimes, where there is a reasonable excuse supported by evidence. We assess honestly whether a case exists before spending your money making it.
What is Time to Pay?
An arrangement with HMRC to pay tax in instalments. It is agreed far more readily once the return is filed and the amount is known.
Several years are missing. What happens?
Penalties apply per year, so the total grows fast — but so does the benefit of acting. We file them together and deal with HMRC as one case.