UK Savings Interest Tax Calculator

It depends on your other income. A basic rate taxpayer has a £1,000 personal savings allowance and a higher rate taxpayer £500, while additional rate taxpayers get nothing. On top of that, anyone whose non-savings income is below £17,570 can use part or all of the £5,000 starting rate for savings. Someone with very little other income can therefore receive over £18,000 of interest tax-free by stacking the £12,570 personal allowance, the £5,000 starting rate and the £1,000 allowance — while a higher earner pays tax on everything above £500.

£1,000 for basic rate taxpayers, £500 for higher rate taxpayers and nil for additional rate taxpayers. The bands are unchanged from previous years. Importantly, the allowance is determined by the band you fall into once the interest itself is added to your income, so a large interest payment can push you from basic rate to higher rate and halve your allowance in the same movement.

Not usually, if you are employed or on a pension and not already in Self Assessment. Banks and building societies report interest to HMRC automatically after the end of the tax year, and HMRC adjusts your PAYE code to collect any tax due. You do have to declare it if you already file a Self Assessment return, or if the interest is large enough to bring you into Self Assessment for another reason — and the legal duty to notify chargeability still rests with you if HMRC does not pick it up.

Yes. UK banks, building societies and NS&I report interest paid to each account holder to HMRC annually. This is why unexpected tax code changes tend to appear the following autumn. The reporting is not always perfect — accounts opened mid-year, joint accounts and accounts held in trust are common sources of error — so it is worth checking the interest figure in your personal tax account against your own statements rather than assuming HMRC has it right.

Through your PAYE code. HMRC estimates your interest for the coming year based on what your bank reported for the last one, and reduces your tax code so the tax is taken from your salary in instalments. This means you can be paying tax on an estimate of interest you have not yet received, and if rates fall or you move money into an ISA the estimate becomes wrong. You can correct it at any time through your personal tax account.

A £5,000 band of savings income taxed at 0%, available only to people with low non-savings income. It is reduced by £1 for every £1 of non-savings taxable income above the personal allowance, so it disappears entirely once your other income reaches £17,570. It is aimed at pensioners and people with small salaries and substantial savings, and it is the single most under-claimed relief in this area because it never appears on a bank statement.

No. Interest earned inside a cash ISA is free of UK income tax and does not use up your personal savings allowance, so it is worth filling ISA capacity before holding cash in a taxable account. The ISA subscription limit is £20,000 for 2026/27 across all ISA types combined. Note that this is a UK exemption only — US citizens resident in the UK get no US benefit from an ISA, and the interest remains fully taxable on their Form 1040.

There is no single figure. If your only untaxed income is bank interest and HMRC can collect the tax through your tax code, you generally do not need to file. You will be brought into Self Assessment if the amounts are large enough that a code adjustment is impractical, or if you have other reasons to file. If you are not already in the system and you do need to file, the deadline to register is 5 October following the end of the tax year.

Yes. Interest forms part of adjusted net income, so it counts towards the £100,000 threshold at which the personal allowance starts to be withdrawn at £1 for every £2. That is what creates the 60% effective marginal rate between £100,000 and £125,140 — and interest can push you into it just as easily as a bonus can. A gross personal pension contribution reduces adjusted net income and is the standard way back out.

Yes, but only £500 rather than £1,000. Additional rate taxpayers, meaning those with taxable income above £125,140, receive no personal savings allowance at all and pay 45% on the first pound of interest. Because the allowance halves at the higher rate threshold, an extra £1 of income that tips you over can cost £200 of tax on interest you had already received — one of the sharper cliff edges in the UK system.

It is taxable in the tax year in which it arises, which for most accounts means when it is credited and available to you. Fixed-rate bonds that credit interest only at maturity are the common complication: if a three-year bond pays everything at the end, all of it can land in one tax year and blow through your allowance, even though it accrued over three. Where interest is credited annually and accessible, it is taxed year by year instead.

It is split equally between the account holders unless you tell HMRC the beneficial ownership is different. Each holder then applies their own personal savings allowance and starting rate. For couples with different marginal rates this is a genuine planning point: moving cash into the lower earner's sole name can produce two full allowances at the lower rate rather than one split across a higher one.

No. Premium Bond prizes are exempt from UK income tax and capital gains tax entirely, and they do not use up your personal savings allowance. They are not, however, exempt from US tax — a US citizen resident in the UK must report Premium Bond winnings as income on their US return, which is a recurring surprise for Americans who assume the UK exemption travels.

Yes. US citizens are taxed on worldwide income regardless of where they live, so UK bank interest goes on your Form 1040 as well as being taxable in the UK. Relief comes through the foreign tax credit on Form 1116, so you generally do not pay twice — but the UK tax has to have actually been paid, and interest sheltered by the personal savings allowance or the starting rate carries no UK tax to credit, leaving US tax genuinely due. The accounts themselves are also reportable on the FBAR once your foreign balances exceed $10,000 in aggregate.

It can. Payments on account are 50% of the previous year's Income Tax and Class 4 National Insurance, and tax on savings interest collected through Self Assessment forms part of that figure. A year with unusually high interest therefore inflates both instalments for the following year, even if rates have since fallen. If you know the interest will not repeat, a reduction claim is available — but get the estimate wrong and HMRC charges interest on the shortfall from the original due dates.