Which tax year does my income belong to?
The UK tax year does not match the calendar: it runs from 6 April to 5 April. Put in a date and see which year a payment belongs to.
Which tax year does my income belong to?
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6 April to 5 April
A tax year starts on 6 April and ends on 5 April. Money received on 5 April belongs to the year that just ended. Money on 6 April belongs to the new one.
Paid date usually decides
Under the cash basis a sole trader records income when they receive money and expenses when they pay a bill, so the date you were paid decides the year. Traditional accounting uses the invoice date instead.
Why it matters
A job done in March and paid in April lands in the next tax year. That can move you across the £1,000 line, or push a deadline back a year.
Figures for the 2026/27 tax year, checked 25 October 2026. Sources: Simpler income tax: cash basis. An estimate, not advice. SideTill is not tax software.
Keep the number for every month
SideTill is the simple record of your side hustle: log the job, send the invoice, record the money when it comes in, and see whether the month actually made you money. It also shows your best month, so you can tell a bad month from a bad habit.
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Questions
Which method am I using?
If you did not choose one, most sole traders are on the cash basis. You must say on your return if you use the traditional method.
What if I invoice in one year and am paid in the next?
On the cash basis it belongs to the year you were paid.
Does this change the Self Assessment deadlines?
The deadlines follow the tax year. See the deadlines page on this site.