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Self Assessment Tax Return Rules

This section is a Self Assessment tax helpline meant for anyone who needs some extra guidance. It explains any new, and current, Self Assessment tax return rules for 2022.

SELF ASSESSMENT HELPLINE: HM Revenue and Customs use the Self Assessment system to collect Income Tax.

According to employment laws, income tax deduction for most employees is an automatic process. It gets taken at source from wages, pensions, and from any relevant savings plans.

But, businesses and anyone with an extra source of income must report that extra revenue in a tax return.

Those who need to send a tax return must fill it in after the end of the tax year that it applies to. The UK tax year is April 6th to the next April 5th.

How to Send a Tax Return

You can send a tax return online or by mail. You will need to register or log in to file a tax return online or send in a paper form instead.

Filing a Self Assessment Tax Return

No matter whether you are self-employed or not (e.g. you send one because you get income from renting out a property), you can still file your Self Assessment tax return online. The online service allows you to:

  • Check your contact details are correct.
  • View previous tax returns.
  • Print out the results of your tax calculation.

Note: You would need to register for Self Assessment before using this service if you didn’t file a tax return in the previous tax year.

You cannot file Self Assessment tax returns online:

You can use the Government Gateway or GOV.UK Verify to prove your identity when you sign in to file your tax return.

Note: HMRC Self Assessment tax return helpline ‘Ffurflenni Treth Hunanasesiad‘ and ‘cyflwyno’ch Ffurflen Dreth Hunanasesiad ar-lein‘ are both available in Welsh language (Cymraeg).

Self-Assessment Tax Return Deadlines

HM Revenue and Customs set deadlines for Self Assessment tax returns. Be sure to send your tax return to HMRC before the deadline. If you file your returns online, the deadline is the 31st of January each year (see below).

Sending tax returns online sometimes need a little extra time to meet the deadline. This will apply most to those who did not send an online return in the previous year.

In this case it is wise to allow up to 20 working days so you can register first. Even so, there are several different ways to register depending on whether you are:

Filling in Tax Returns

You can get further help to fill in your tax return if you need it. The best way to fill it in correctly is to keep proper records of your transactions through the year. As a rule, ‘keeping your pay and tax records’ is going to include bank statements and all sales receipts.

Paying Self Assessment Bill

HM Revenue and Customs calculate the amount owed based on the report you send in. You should pay your Self Assessment tax bill before January the 31st. But, the deadline is the 30th of December if HMRC collect the tax automatically from wages or a pension.

Note: There are different Income Tax rates (tax bands) that determine how much tax you need to pay. Different rates also apply for Capital Gains Tax if you need to pay it (e.g. after selling a second home or equities).


Self Employed Business Records

Learn how to do accounts for self employed sole traders and partnerships. Check your responsibilities for keeping business records if you are self-employed.

Who Needs to Send a Tax Return?

Each tax year runs from the 6th of April to the 5th of April in the following year. Check who needs to file a Self Assessment tax return in the United Kingdom.

Tax Return after a Death

There may be situations where you need to file a tax return for someone who has died. Check out the process for reporting and filing taxes for a deceased person.

Self Assessment Tax Returns


There may be circumstances when you need to change a tax return after you filed it. Check how to make Self Assessment tax return corrections if you make a mistake.


HMRC set tax return time limits with penalties for receiving late returns or payments. You must pay any money owed before the Self Assessment deadlines to avoid a penalty.


A government tool gives an estimate of penalties and interest for missing a deadline. Even so, it will only calculate a penalty approximation for the current year.

HMRC Self Assessment Helpline Guide

There are several ways you can get help with Self Assessment tax returns, including:

Further Guidance and Help Filling in a Tax Return

HMRC Self Employed Ready Reckoner

HMRC Notes and Self Assessment Helpsheets

Note: The HMRC video contains further information on what expenses you can include in your Self Assessment tax return.

Tax Return Self Assessment Rules and Procedures in United Kingdom