Get an estimate of how much you’ll need to pay in penalties and interest if you’ve missed the deadline for:

  • sending your Self Assessment tax return
  • paying your Self Assessment tax bill

This calculator can only give an estimate of what you owe and does not take account of:

  • payments you’ve made towards your tax bill
  • outstanding interest or penalties for previous tax years
  • credit you have from previous tax years

Do not use the calculator if you:

  • got your request to fill in a Self Assessment less than 3 months before the deadline, so had more time to file it
  • sent a paper return after October 31, but HMRC agreed you had a reasonable excuse to not file online

If your 2018-19 tax return is more than 3 months late, your calculation may be wrong. This is because daily penalties are not being charged for the 2018-19 tax year, because of coronavirus.

You’ll still be charged £100 for missing the deadline, as well as further penalties if your tax return is more than 6 months late.

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