Corporation Tax late filing penalties after the April 2026 doubling
Checked 18 July 2026 · How we check our figures
What it is
A late Company Tax Return meets two layers under Sch 18 FA 1998: flat penalties that arrive automatically, and tax-geared penalties of 10 per cent that attach to unpaid Corporation Tax at 6 and 12 months. Directors meet the first layer as a late company tax return fine. The dates matter more than they used to: for returns with a filing date on or after 1 April 2026 the flat penalties doubled, the first change since 1998, and they land even where no tax is due, dormant companies included, so long as HMRC expects a return (gov.uk, server-verified 2026-07-18).
Reading the notice
The flat layer for filing dates from 1 April 2026: 200 pounds the day after the deadline, a further 200 once 3 months pass, 400 in total; a third late year in a row raises the figures to 1,000, or 2,000 where that return is more than 3 months late (gov.uk, server-verified 2026-07-18; the older figures and the old and new comparison live in the calculator at /fines/corporation-tax-late-filing).
The tax-geared layer is unchanged: at 6 months late HMRC can determine the bill by estimate and add 10 per cent of the unpaid tax, and at 12 months a further 10 per cent (gov.uk).
Which regime applies follows the return's filing date, not the day the return eventually arrives.
The decision in front of you
File the return, however late: it stops the flat layer, replaces HMRC's estimate with real figures, and in practice HMRC expects the return to be in before an appeal is entertained.
Pay the Corporation Tax even while the return lags: the tax-geared 10 per cents attach to unpaid tax, so a paid bill takes their base away.
Appeal with a reasonable excuse within 30 days of the penalty notice (gov.uk).
Do nothing and HMRC writes the return for you: a determination estimates the bill, the estimate is rarely generous, and the 10 per cent stages then price the estimate (gov.uk).
What happens next
The same missed year end has a second regulator: the accounts side at Companies House penalises independently, the companies house late filing guide.
Interest runs daily on unpaid Corporation Tax alongside every penalty here, the hmrc interest guide's territory.
The flat amounts, static since 1998, are now the kind a Budget can move: the dated steps and the old regime comparison live in the calculator at /fines/corporation-tax-late-filing.
The numbers
Flat penalties for filing dates from 1 April 2026: 200 pounds, then 400 in total after 3 months; 1,000 and 2,000 for a third consecutive late year (gov.uk, server-verified 2026-07-18).
Tax-geared: 10 per cent of unpaid Corporation Tax at 6 months and a further 10 per cent at 12 (gov.uk).
Earlier filing dates run on the pre-2026 figures: see the calculator at /fines/corporation-tax-late-filing, where both tables sit dated.
The deadlines
The return is due 12 months after the end of the accounting period, while the tax is due earlier, 9 months and 1 day after it: the money deadline comes before the paperwork deadline (gov.uk).
The flat layer steps at day 1 and 3 months; the tax-geared layer at 6 and 12 months (gov.uk).
30 days from the penalty notice to appeal (gov.uk).
What people get wrong
Letting a dormant company drift: the flat penalties do not ask about the tax bill, only whether an expected return arrived, and a company never told HMRC it was dormant is still expected (gov.uk).
Reading the doubling by the calendar of filing: the 2026 figures follow the return's filing date, so an old return filed today can still price on the old table.
Solving the tax and forgetting the form: paying removes the 10 per cent base but leaves the flat layer climbing, because the two layers never talk to each other.
Authority
Sch 18 FA 1998, as amended following Autumn Budget 2025; gov.uk, Company Tax Returns penalties