Interest Income: How It Is Taxed for UK Individuals
Interest income is one of the most common forms of investment income for UK individuals, yet it is also an area that frequently causes confusion. Many people assume that interest earned on savings is either entirely tax-free or automatically dealt with by their bank. In reality, while a number of allowances and exemptions may apply, interest income is fully within the scope of the UK income tax system and must be considered carefully.
This article explains how interest income is taxed for UK individuals, the allowances that may apply, how different sources of interest are treated, and when action may be required to report interest to HM Revenue & Customs (HMRC).
What counts as interest income?
Interest income can arise from a wide range of sources, including:
- Savings and current accounts with banks and building societies
- Fixed-term and notice deposit accounts
- Corporate bonds and loan notes
- UK government gilts
- Peer-to-peer (P2P) lending platforms
- Certain unit trusts and open-ended investment companies (OIECs)
- National Savings & Investments (NS&I) products
For most individuals, interest income will primarily arise from cash savings held with banks or building societies, particularly where interest rates have increased in recent years. Even modest balances can now generate levels of interest that exceed available tax-free allowances.
When does interest become taxable?
As a general rule, interest is taxable in the tax year in which it arises, meaning when it is paid, credited to an account, or otherwise made available. This is important where interest is rolled up annually or paid at maturity, as it may still be treated as arising earlier depending on the terms of the account.
Interest is subject to income tax unless a specific exemption applies. Unlike employment income, most interest is paid gross, with no tax deducted at source. This means that responsibility for identifying whether tax is due ultimately rests with the individual.
Tax-free interest: common exemptions
Certain types of interest are fully exempt from income tax. The most common examples include:
Individual Savings Accounts (ISAs)
All interest earned within an ISA is completely tax-free, regardless of the amount or the individual’s tax band. This applies to both cash ISAs and stocks and shares ISAs.
Premium Bonds
Premium Bond “prizes” are not treated as interest and are outside the scope of income tax.
Certain NS&I products
Some NS&I products pay tax-free interest, while others are taxable. The specific terms of the product should always be checked.
Personal injury compensation
Interest on damages or compensation for personal injuries may be exempt from tax in limited and specific circumstances.
These exemptions apply automatically, and exempt interest does not need to be declared to HMRC.
UK residents and overseas interest
Individuals who are resident in the UK for tax purposes are generally liable to UK income tax on their worldwide income, including interest earned on overseas bank accounts and investments.
Overseas interest must usually be declared on a self-assessment tax return, even if:
- the interest remains overseas, or
- foreign tax has already been deducted.
Where foreign tax has been paid, a foreign tax credit may be available to offset the UK tax liability, up to the amount of UK tax due on that income. Double taxation agreements may also apply, depending on the country involved.
Interest from joint accounts
Where interest arises on a joint account, it is normally treated as belonging to the account holders in equal shares, regardless of who contributed the funds.
However, if the funds are owned in unequal proportions and there is clear evidence to support this (for example, documentation showing beneficial ownership), HMRC may accept an alternative allocation of the interest for tax purposes.
The personal savings allowance (PSA)
Once it has been established that interest is taxable, the next key consideration is the personal savings allowance (PSA). This allowance allows many individuals to receive a certain amount of savings income tax-free each tax year.
The level of the PSA depends on the individual’s marginal rate of income tax:
- Basic-rate taxpayers (taxable income up to £50,270 for 2025/26)
Can receive up to £1,000 of interest tax-free. - Higher-rate taxpayers (taxable income between £50,271 and £125,140)
Can receive up to £500 of interest tax-free. - Additional-rate taxpayers (income over £125,140)
Do not benefit from the PSA; all interest is taxable.
The PSA applies automatically, but individuals must still identify whether their interest exceeds the allowance.
Interaction with the personal allowance
In addition to the PSA, individuals may also benefit from the personal allowance, which is £12,570 for the 2025/26 tax year.
If an individual’s total income, including savings income, does not exceed the personal allowance, income tax will generally not arise. This means that individuals with low overall income may not pay tax on interest even if it exceeds the PSA.
However, once total income exceeds the personal allowance, savings income is brought into charge and must be considered alongside other allowances.
The starting rate for savings
There is also a lesser-known but potentially valuable relief known as the starting rate for savings.
This provides a 0% tax rate on up to £5,000 of savings income, provided that non-savings income (such as salary, pension income or trading profits) is sufficiently low.
The starting rate is reduced by £1 for every £1 of non-savings income above the personal allowance. For example:
- If non-savings income is £13,570 (i.e. £1,000 above the personal allowance), the starting rate band is reduced to £4,000.
- If non-savings income exceeds £17,570, the starting rate is reduced to nil.
Interest falling within the starting rate band is taxed at 0%, before the PSA is applied.
Order in which income is taxed
For income tax purposes, different types of income are taxed in a specific order:
-
Non-savings income (employment income, pensions, trading income)
-
Savings income (including interest)
-
Dividend income
This ordering matters because interest income can push an individual into a higher tax band. For example, someone whose non-savings income already uses most of the basic rate band may find that some or all of their interest is taxed at 40%.
How and when tax on interest is paid
Most individuals do not pay tax on interest automatically when it is received. Instead, HMRC may collect the tax in one of two ways:
Adjustment to PAYE tax code
Where interest income is relatively modest and HMRC is aware of it (for example, through information provided by banks), HMRC may adjust the individual’s PAYE tax code so that tax is collected through salary or pension payments.
Self-assessment tax return
Individuals may need to complete a self-assessment tax return where:
- savings income is significant,
- they already complete a tax return for other reasons, or
- HMRC requests a return.
Even where tax is collected through PAYE, individuals remain responsible for ensuring that the correct amount of interest has been reported.
Record keeping and reporting obligations
Banks and building societies report interest paid to HMRC, but this does not remove the need for individuals to keep their own records.
It is good practice to retain:
- annual interest certificates or statements,
- details of overseas accounts and investments,
- evidence of foreign tax deducted.
Failure to declare taxable interest can result in penalties and interest charges, particularly where HMRC considers the omission to be careless or deliberate.
Practical tip: children’s savings
Interest on savings held for children is generally treated as the child’s income. However, special anti-avoidance rules apply where a parent gifts money to a child.
If interest arising from a parental gift exceeds £100 per year per parent per child, the interest is taxed as the parent’s income, not the child’s. This rule does not apply to gifts from grandparents or other relatives.
Conclusion
Interest income is a routine but often overlooked part of the UK tax system. While many individuals will not pay tax due to the availability of the personal allowance, the starting rate for savings and the personal savings allowance, rising interest rates mean that more people are now affected.
Understanding how interest is taxed, keeping accurate records and reviewing savings arrangements regularly can help avoid unexpected tax bills and ensure compliance with HMRC requirements.
Where savings income is substantial, involves overseas accounts, or interacts with higher tax bands, professional advice can help ensure that the correct amount of tax is paid and that available allowances are used effectively.
