What happens if I file my tax return late?

HMRC charges penalties that stack up the longer you leave it. Here's how it works: an automatic £100 penalty from the day after the deadline, regardless of whether you owe any tax; after 3 months, £10 per day for up to 90 days (up to £900); after 6 months, a further penalty of 5% of the tax due or £300, whichever is higher; after 12 months, another 5% or £300. Interest is also charged on any unpaid tax. The key thing: filing as soon as possible stops the daily charges. If you can't pay the bill, file anyway — that limits penalties to the late payment side only. You can then contact HMRC about a Time to Pay arrangement to spread the cost. We can help you file even if you're already late — just message us on live chat.