What is the 5 October deadline for?

It is the date you must tell HMRC you became self-employed or started earning untaxed income, so you can be set up for Self Assessment. For income earned in the 2025 to 2026 tax year, the deadline is 5 October 2026.

Do I need to register if I only made a few hundred pounds?

Usually not. If your gross self-employed income was £1,000 or less, the trading allowance generally means you do not have to register. You might still choose to, for example to pay voluntary National Insurance or claim a loss.

Is registering the same as paying my tax?

No. Registering just puts you in the system. Your return and any tax for 2025 to 2026 are not due until 31 January 2027.

What happens if I register late?

HMRC can charge a failure-to-notify penalty. It is based on the tax you owe and how late you are, so it grows the longer you wait, and it can apply even when the tax itself is small.

How long does it take to get set up?

Not instant. HMRC posts you a Unique Taxpayer Reference after you register, and you cannot file without it, so leave time rather than registering right on the deadline.

NOT financial advice - seek advice from a professional for your specific situation

TaxKilnUK tax guidance

Going self-employed? You must tell HMRC by 5 October

By TaxKiln on 28 June 2026

If you started working for yourself in the last tax year, you must register with HMRC by 5 October. Miss it and you can be fined before you owe any tax.

Loading…