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Which? Tax calculator 2017-18

Independent, tailored help with your income tax return

Calculate and submit your self-assessment tax return online

We've teamed up with SimpleTax to bring you an online self-assessment tool allowing Which? members to calculate their tax return and submit it directly to HMRC for just £10 (£30 for non-members).

  • Easy to use and jargon-free personal tax calculator
  • Safe and secure - protected by 256-bit encryption
  • A simple and quick way to calculate your tax return
  • Officially recognised by HMRC
  • Tips that could save you money on allowances and expenses you might have missed
Start calculating

Supported income types

  • Employment - SA102 Full/Short
  • Self-employment - SA103 Full/Short
  • Interests and dividends - SA100
  • Property - SA105
  • Income from pensions - SA100
  • Ministers of Religion - SA102M
  • Partnership - SA104 Full/Short
  • Residency - SA109
  • Foreign - SA106
  • Trust - SA107
  • Capital Gains - SA108

Become a Which? member and submit for just £10 (£30 for non-members)

Sign up to Which? for £1

100% online, recognised by HMRC

Easy to understand forms

Stay on top of your tax money

Nothing to install, runs everywhere

Do I need to complete a self-assessment tax return?

If HMRC has asked you to complete a self-assessment return for 2017-2018, you must complete it before 31 January 2019 or face a £100 fine. Some people (those who are self-employed, for example) need to complete a tax return every year; others are sent one because they have untaxed income (often from property).


Although the publisher endeavours to make sure the information in this calculator is accurate and up-to-date, it is only a general guide nothing in it constitutes taxation advice by Which?. You should consult a qualified tax adviser who can consider individual circumstances if taxation advice is required. Which? Limited does not accept any liability for any loss or damage suffered as a consequence of relying on any information contained in this guide.