You’ll get a penalty if you need to send a tax return and you miss the deadline for submitting it or paying your bill.

You’ll get a penalty of £100 if your tax return is up to three months late. You’ll have to pay more if it’s later, or if you pay your tax bill late. You’ll also be charged interest on late payments.

HMRC provide a tool to help you estimate your penalty for Self Assessment tax returns more than three months late and late payments.