What late actually costs, and why the appeal usually fails
The penalty ladder is published, automatic and doubles. The appeal grounds are published too, and the list of reasons that do not work reads like a list of the reasons people actually have.
The ladder
For a private limited company filing accounts late at Companies House: 150 pounds up to one month, 375 pounds from one to three months, 750 pounds from three to six months, and 1,500 pounds beyond six months.
The penalty notice arrives automatically after the deadline. Nobody calls first, and the figure doubles if the accounts are late two years in a row.
It is not only money
Persistently failing to send accounts or a confirmation statement can get the company struck off the register. Companies House says so on the same page as the penalty table.
Corporation Tax runs a separate penalty regime at HMRC, on top of the Companies House one. Two filings, two regimes, two sets of consequences.
How an appeal is supposed to work
An appeal has to give a specific reason for not filing on time, include the relevant dates and details, and show the circumstances were out of your control. GOV.UK's example is a fire that destroyed the records days before the accounts were due.
Companies House does not collect the penalty while the appeal is being considered.
The reasons that do not work
GOV.UK lists the grounds that usually fail, and the list is uncomfortably specific: these were your first accounts, the company was dormant, you could not afford to pay, another director was responsible, it was your accountant's fault, you did not know when or how to file, the accounts were delayed or lost in the post, and the directors live or were travelling overseas.
That last one is not a footnote for this audience. Living abroad is the normal state of the people this notebook is written for, and it is explicitly on the list of reasons that will not save a late filing.
If the first appeal fails you can write to a senior casework manager, then to the independent adjudicators, then to the Registrar of Companies. The order is fixed and skipping a step means the registrar will not look at it.
The dates for your own company come out of the deadline calculator, and the filing itself is described in the dossier.