You may need to complete Self Assessment if you have income from savings and investments above certain amounts.
If you have income from savings of more than the exempt amount (£1,000 or £500 for higher rate taxpayers for the 2025/26 tax year) you must tell HMRC.
If your total income from both savings and investments is more than £10,000 you must register for Self Assessment.
There is also a £5,000 starting rate for savings, which means you can have up to £5,000 in your savings and not pay tax on it. But this is only available when other income (for example, employment income or pensions) is less than £17,570.
The records you need to keep.
Most people get an annual statement from their bank or building society which shows the total amount of interest you’ve received
If you don’t get this, you will need to look through your bank or building society details and add it up yourself. You should keep a copy of your calculation of the total.
Most interest from banks or building societies is paid without any tax taken off. But if tax has already been taken out, you should report both the amount you received after tax (called “net interest”) and the amount of tax that was taken.
If you receive dividends from UK companies you need to report each one separately, and include the total amount paid by each company.