Late-filing penalty calculator
Late Self Assessment? See roughly what it's cost so far — and why filing this week beats filing next month, every time.
How the penalties stack
Miss 31 January and £100 is charged immediately — even if you owe no tax. Three months late, daily £10 penalties start (up to £900). At six months, HMRC adds the greater of £300 or 5% of the tax due; at twelve months, the same again. Separately, late payment attracts 5% surcharges at 30 days, 6 months and 12 months, plus daily interest.
The good news
Filing stops the filing-penalty clock instantly, and penalties with a reasonable excuse — serious illness, bereavement, HMRC's own failures — can be appealed and often are cancelled. What never works is waiting. Our late-return rescue is a £179 fixed fee: we file fast and appeal what's appealable.