Did you have a new source of taxable income in 2024/2025?

If you have a new source of income that is not taxed at source, you may need to register with HMRC for Self-Assessment. This applies if you became self-employed during the 2024-25 tax year, started receiving rental income, made significant savings or investment gains, or became a company director.

The deadline to register for Self-Assessment for the 2024-25 tax year was 5 October 2025. This is an important cut-off. If you missed it, you risk HMRC penalties and delays in getting your tax affairs in order.

Who must register

You will need to register with HMRC if, during the tax year to 5 April 2025, you:

·       Became self-employed as a sole trader and earned more than £1,000 before expenses.

·       Received rental income from letting property.

·       Became a partner in a business partnership.

·       Were a company director and received untaxed income.

·       Had capital gains that need to be reported.

·       Earned income from savings, investments, or overseas sources that has not been taxed.

·       Received dividends or other income where tax may still be due.

Taxpayers already in the Self-Assessment system do not need to register again. This requirement is mainly for those who need to file for the first time, or who have a new source of income not previously disclosed.

How to register

Registration is conducted online via the GOV.UK website. Once you register, HMRC will issue you with a Unique Taxpayer Reference (UTR) and set you up to file returns either online or on paper.

If you have never registered before, allow time for HMRC to process your application and send your UTR. Leaving registration until the last minute can make it difficult to submit your tax return on time.

What happens next

Once registered, you must file a tax return covering income received between 6 April 2024 and 5 April 2025. If you file on paper, the deadline is 31 October 2025. If you file online, the deadline is 31 January 2026. Any tax due must also be paid by 31 January 2026.

Action point

If you started a new business, received rental or investment income, or had any other untaxed income in the year to 5 April 2025, you may need to register. on or before 5 October 2025.

Please get in touch if you missed the 5 October deadline or if you are unsure. We can help confirm whether registration is needed and guide you through the process.