HMRC Tax, interest and penalty calculator

Reviewed by Mike Parkes, technical director at GoSimpleTax.

Business owner with calculator working out tax

If your tax affairs are relatively straightforward - for example, you are only entitled to basic personal allowances - you can use the HMRC calculator to work out your Income tax, Class 4 National Insurance contributions, and any interest and penalties due for tax years ended 5 April 2010 to 5 April 2021 inclusively.

HMRC Income Tax, interest and penalty calculator >>

Do you need to file a tax return?

You must send a tax return if, in the last tax year, you were:

  • self-employed and earned more than £1,000
  • a partner in a business partnership

You may also need to file a tax return if you have other income, such as:

  • money from renting out a property
  • tips and commission
  • income from savings, investments and dividends
  • foreign income

Tax deadlines

For the tax year 6 April 2022 to 5 April 2023:

  • paper tax returns 31 October 2023
  • online tax returns 31 January 2024
  • payment of tax owed 31 January 2024

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