ISA allowance levels for the 2025/2026 tax year

The annual ISA subscription limit is £20,000 for adults and £9,000 per child for Junior ISAs in the 2026/27 tax year, which runs from 6 April 2026 to 5 April 2027, according to NS&I, the UK government savings bank¹. Which? reports the same figures and notes the adult allowance is unchanged from 2025/26². The ISA allowance covers deposits across cash ISAs, stocks and shares ISAs and other eligible types, and can be split between them in any proportion¹.

From 6 April 2027, the start of the 2027/28 tax year, the amount under-65s can pay into cash ISAs will be cut to £12,000 a year, while the overall £20,000 limit continues to apply across all types of ISA¹. NS&I states that savers could still pay up to £8,000, the remaining portion of the overall allowance, into stocks and shares ISAs or other eligible ISAs¹. The change applies only to new deposits made from April 2027 and does not affect money already contributed to cash ISAs¹. People aged 65 or over are unaffected and keep a £20,000 cash ISA allowance for 2027/28¹.

Source: NS&I¹

Unused allowance does not roll over. NS&I gives the example that depositing £10,000 in one year does not allow a £30,000 deposit the following year to make up the difference¹. Which? states that any unused allowance is lost at the end of the tax year and starts anew on 6 April². Money held in ISAs remains free of UK Income Tax and Capital Gains Tax while it stays in the ISA¹.

Some accounts are flexible, meaning money can be withdrawn and replaced without the replacement counting further towards the allowance, provided the top-up happens in the same tax year the withdrawal was made². This flexibility is not compulsory and is not available on all ISAs, and it does not apply to Junior ISAs or lifetime ISAs². Coventry Building Society notes that fixed rate cash ISAs do not permit withdrawals within the fixed term, and that closing the account early will likely incur a charge³.

On Junior ISAs, the £9,000 limit is unchanged from 2025/26, and contributions do not come out of a parent's own ISA allowance because the account belongs to the child². A child can hold one cash Junior ISA and one stocks and shares Junior ISA at the same time². Coventry Building Society states that the account converts into an adult ISA when the child turns 18³.

Why it matters for households

For the 2026/27 tax year, the amount that can be sheltered from tax is unchanged: £20,000 per adult and £9,000 per child¹. The practical change is dated to 6 April 2027, when under-65s will be limited to £12,000 of new cash ISA deposits in that tax year, with the remaining £8,000 of the overall allowance still usable in stocks and shares or other eligible ISAs¹. Savers aged 65 or over on that date keep the £20,000 cash ISA allowance¹. Existing cash ISA balances are unaffected by the cap, which applies only to new deposits from April 2027¹. Households where one saver turns 65 during 2027/28 face uncertainty, because NS&I says the rules for that group will be clarified after an industry consultation in 2026¹.

What happens next

Nothing changes before April 2027, and NS&I states that no immediate action is needed¹. The treatment of savers who turn 65 part-way through the 2027/28 tax year will be set out after an industry consultation in 2026¹.