Accountants in Cardiff

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The online deadline for the next tax return submission is 31st January 2026

Although the deadline is 31 January 2026, you can submit your tax return anytime from 6 April 2025

What are the benefits of submitting your tax return early?

• Peace of mind
• Receiving a tax refund sooner
• No late penalty fee
• If you do have a tax bill to pay, submitting your return early will give you time to budget

What is a Self-Assessment Tax Return?

A Self-Assessment is a form which needs to be submitted to the HMRC by 31 January for the tax year 6 April to 5 April every year. It can be submitted anytime after the 6 April however, the majority of people will leave this until the end of the year before the deadline. This form includes your taxable income and capital gains if appropriate. Tax allowances and tax reliefs are also taken into account. The information on the form basically calculates to the HMRC whether you have overpaid or underpaid tax. This means you could be due to tax refund or you could owe the HMRC money which will need to paid to them by 31 January.

Do I need to complete a Self-Assessment Tax Return? 

It is more than likely you will need to submit a tax return if you receive an income other than through PAYE (Pay As You Earn). Check out the link below for a breakdown on who needs to complete a tax return.

https://www.gov.uk/self-assessment-tax-returns/who-must-send-a-tax-return 

How do I register for Self-Assessment Tax Return?

This can be done through HMRC’s online service. Following registration, you will receive a Unique Tax Reference (UTR) number which is 10 digits long. You will be sent an activation code to log into your online account with.