Tax and interest
Whether ISA interest is taxable, how the savings allowances work and whether an ISA goes on a tax return.
For information only, not financial advice.
Guides on how ISAs are taxed compared with other savings and investments, what gov.uk says about declaring them, and worked examples of the interest they can earn.
Quick answers
Is ISA interest or growth taxed?
gov.uk says you do not pay tax on interest on cash in an ISA, or on income or capital gains from investments in an ISA.
Does ISA interest go on a tax return?
gov.uk says you do not need to declare ISA interest on a tax return.
Rules data last checked against gov.uk on 26 September 2026. For information only, not financial advice.
Tools for this topic
ISA vs Savings Calculator
Compare a cash ISA with a taxable savings account.
Cash ISA Calculator
Estimate the interest a cash ISA could earn at a rate you choose.
Guides
- Is ISA Interest Taxable? The Short Answer and the Detail
Is interest in an ISA taxed? How ISA interest compares with a normal savings account, with a worked example and the allowances that apply outside an ISA.
- Do You Need to Declare an ISA on a Tax Return?
gov.uk says ISA interest, income and gains need not be declared on a tax return. What that covers, what still matters, and what differs outside an ISA.
- ISA Tax Implications: What UK Savers Often Overlook
Interest, dividends and gains in an ISA are not taxed, but inheritance, moving abroad, paying in too much and Lifetime ISA withdrawals can matter.
- Cash ISA Interest: Worked Examples at Different Rates
See how Cash ISA interest is worked out, with tables for £6,000, £10,000 and £15,000 at assumed rates, plus a five-year example with monthly payments.
- ISA vs Pension: How Does the Tax Treatment Differ?
How tax applies to money paid into, held in and taken out of an ISA and a pension, as gov.uk describes it. Differences only, not advice.
See also the ISA rules at a glance, the ISA glossary and all topics.