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Self Assessment Tax Returns

Self Assessment Tax Return Rules

This section is a Self Assessment helpline meant for anyone who needs some extra guidance. It explains the new Self Assessment tax return rules for 2018.

SELF-ASSESSMENT OVERVIEW: 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. 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.

Note: There is also a Welsh language version of this guide (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 then the deadline is the 31st of January each year.

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, these records will 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).

Also in this section...

Self Employed Business RecordsSelf Employed Business Records

BASIC ACCOUNTING: 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 Must Send a Self Assessment Tax Return?Who Needs to Send a Tax Return?

WHO MUST 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.


Self Assessment Tax Return Deadlines GuideSelf Assessment Tax Return Deadlines

SELF ASSESSMENT DEADLINES: HMRC set tax return time limits with penalties for receiving late returns or payments. You must pay any money owed before the Self Assessment deadline 2016/17.

SELF-ASSESSMENT PENALTIES: A government tool gives an estimate of penalties and interest for missing a deadline. But, it will only calculate a penalty approximation for the current year.

SELF-ASSESSMENT CORRECTIONS: 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.


Who Must Send a Self Assessment Tax Return?Tax Return for Someone who has Died

TAX RETURN AFTER 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 Helpline and Advice GuideSelf Assessment Helpline and Advice

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


Self Assessment Tax Return Rules in the United Kingdom