Do I need to declare my savings interest?

It depends on how much interest you received and what type of taxpayer you are. For 2025/26, the Personal Savings Allowance is £1,000 for basic-rate taxpayers and £500 for higher-rate taxpayers. Additional-rate taxpayers (income over £125,140) get no allowance at all. Interest from ISAs is always tax-free and never needs to be declared. If your savings interest exceeds your allowance, you'll need to declare the excess on your Self Assessment return. Banks report interest to HMRC automatically, so it's worth declaring it correctly even if you think the amount is small.