The adult ISA allowance for the 2026/27 tax year is £20,000. This is the maximum you can put into all ISAs combined between 6 April 2026 and 5 April 2027, across cash, stocks and shares, innovative finance and Lifetime ISAs. You can put all of it into a cash ISA, or split it between cash and stocks and shares ISAs.
How much can you put in a cash ISA in 2026/27?
| Item | 2026/27 figure | Source |
|---|---|---|
| Tax year dates | 6 April 2026 to 5 April 2027 | NS&I, 2026 |
| Adult ISA allowance (all types combined) | £20,000 | GOV.UK, 2026; NS&I, 2026 |
| Carry-over of unused allowance | Not permitted | NS&I, 2026 |
The allowance applies to money you pay in. Interest earned inside the account does not count as a new deposit against it.
The fiche used for this section does not confirm the minimum age for opening a cash ISA.
What is the overall ISA allowance?
For the 2026/27 tax year (6 April 2026 to 5 April 2027), the adult ISA allowance is a single £20,000 pot. This is the maximum you can save across all ISAs combined. It is not a separate limit for each account type. Four ISA types draw from this one pot:
- Cash ISA
- Stocks and shares ISA
- Innovative finance ISA
- Lifetime ISA
Any amount paid into one of these counts against the same £20,000 total, so the sum of your deposits across every eligible ISA must stay within it.
The allowance applies to each adult, not to a household. Two adults each have their own £20,000 allowance for the year, and one person’s unused allowance cannot be transferred to another.
What changes for cash ISAs in April 2027?
From 6 April 2027, savers under 65 can pay at most £12,000 a year into cash ISAs. The other £8,000 of the £20,000 adult ISA allowance can go into stocks and shares ISAs or other eligible ISAs. The cap applies only to new deposits.
How the £12,000 cap divides the allowance
| Allowance component | Limit from 6 April 2027 | Source |
|---|---|---|
| Cash ISA deposits (under 65) | £12,000 a year | NS&I, 2026 |
| Stocks and shares ISA or other eligible ISA | £8,000 (the remainder of £20,000) | NS&I, 2026 |
| Total adult ISA allowance | £20,000 | NS&I, 2026 |
The cap is a ceiling on the cash share of the allowance, not a new total.
Practical steps before the change
- Add up the cash ISA deposits you expect to make in a year.
- Compare the total with £12,000. Any amount above that cannot go into a cash ISA.
- Plan the remaining amount, up to £8,000, for a stocks and shares ISA or another eligible ISA type. The fiche names innovative finance and Lifetime ISA as ISA types, though eligibility for each is set by its own rules.
What the cap does not change
Existing cash ISA balances stay where they are. Nothing in the cap requires you to withdraw or move money already saved in a cash ISA. The limit only affects deposits made from 6 April 2027 onward.
Are over-65s affected by the £12,000 cap?
No. Savers aged 65 and over keep the full £20,000 cash ISA limit from April 2027, so the £12,000 annual cap on new cash deposits applies only to savers under 65. From April 2027, people aged 65 and over keep the full £20,000 cash ISA limit, so they can put their whole ISA allowance into cash if they choose.
| Saver group | Maximum new deposits into cash ISAs per year (from the 2027 change) |
|---|---|
| Under 65 | £12,000 (the other £8,000 of the £20,000 allowance can go into stocks and shares or other eligible ISAs) |
| 65 and over | £20,000 (the full adult ISA allowance) |
The rule for people who turn 65 during a tax year has not been published yet. NS&I states that this will be clarified after an industry consultation in 2026, so there is no confirmed treatment for a birthday that falls partway through the 6 April to 5 April tax year. The same applies to any mid-year change of age category: the rules are pending that consultation.
Until the outcome is published, avoid planning deposits on the assumption that either the £12,000 cap or the full £20,000 cash limit applies for the whole tax year in which your 65th birthday falls. Check the GOV.UK and NS&I ISA pages for updated guidance before making a large cash deposit in that year.
Can you split your allowance between ISAs?
The adult ISA allowance for 2026/27 (6 April 2026 to 5 April 2027) is £20,000, and you can divide it between cash ISAs and stocks and shares ISAs in any proportion you choose. Your split decides how much of the allowance is held as cash and how much is invested.
You can put the whole amount in one type, or divide it between both. Each split is your own decision, and no minimum amount is required for either type.
One point shapes how you record a split:
- Several accounts of the same type are allowed: you can pay into more than one ISA of the same type in a tax year, as long as your total deposits across all ISAs stay within the £20,000 allowance. Check the provider’s terms, because some providers do not accept new deposits or transfers into additional accounts.
Illustrative splits of the £20,000 are shown below. These are arithmetic examples, not recommendations.
| Example | Cash ISA deposits | Stocks and shares ISA deposits | Total |
|---|---|---|---|
| All in cash | £20,000 | £0 | £20,000 |
| Even split | £10,000 | £10,000 | £20,000 |
| Mostly invested | £5,000 | £15,000 | £20,000 |
To apply a split, track deposits to each account from 6 April 2026 onward. Once the total reaches £20,000, you cannot pay any more into ISAs for 2026/27.
Does unused ISA allowance carry over?
No. Unused allowance does not carry over to the next tax year. Any part of your annual ISA limit that you do not pay in during a tax year is lost when that year ends, and it is not added to the following year’s limit. The adult limit for 2026/27 (6 April 2026 to 5 April 2027) is £20,000, and that figure applies in full whatever was left unused before.
The annual limit works as a per-year cap, not a running balance. Each tax year has its own limit, and only deposits made within that year count against it.
Worked example (hypothetical figures):
| Item | Amount |
|---|---|
| Unused allowance left at the end of 2025/26 | £5,000 |
| Amount added to the 2026/27 limit | £0 |
| Total adult ISA limit for 2026/27 | £20,000 |
In this example, the saver’s 2026/27 limit is £20,000, not £25,000. The £5,000 is not recoverable.
What about Junior ISAs?
A Junior ISA has its own annual allowance of £9,000 per child. Each eligible child gets a separate Junior ISA allowance, so a family with two children can pay up to £18,000 in total across two Junior ISAs in the same tax year. The limit applies per child, not per household.
The Junior ISA allowance is a separate limit from the adult £20,000 ISA allowance. Money paid into a child’s Junior ISA does not reduce a parent’s or any other adult’s £20,000 allowance, and an adult’s ISA deposits do not reduce the child’s £9,000 limit. A parent can therefore fund a child’s account and still use their own full adult allowance.
| Allowance | Amount | Scope |
|---|---|---|
| Junior ISA | £9,000 | Per child |
| Adult ISA | £20,000 | Per adult, split across ISA types |
Before opening a Junior ISA, check the age and residency conditions with the provider or on GOV.UK. These criteria are not covered by the verified source data for this article, so confirm them against the current official guidance rather than relying on this page.
Key dates for the tax year
The ISA tax year runs from 6 April to 5 April of the following year. The current year, 2026/27, runs from 6 April 2026 to 5 April 2027. As of late October 2026, about five months remain in it.
| Tax year | Start date | End date | Relevant limit |
|---|---|---|---|
| 2026/27 | 6 April 2026 | 5 April 2027 | £20,000 total ISA allowance for adults |
| 2027/28 | 6 April 2027 | 5 April 2028 | Under-65 cash ISA cap of £12,000 starts |
The allowance is measured per tax year, not per calendar year or per account. Any deposit made between 6 April 2026 and 5 April 2027 counts toward the 2026/27 limit.
The new allowance period begins on 6 April 2027. This is the same date that the cash ISA cap for savers under 65 takes effect, so the start of the 2027/28 tax year is also the first day the cap applies. Savers should therefore treat 6 April 2027 as the date on which the cap rules change, and plan any cash ISA deposits around that boundary.
The source for these dates is NS&I (2026) and GOV.UK (2026). The fiche does not give a clarification date for the rules affecting savers who turn 65 during a tax year. NS&I says these will be clarified after an industry consultation in 2026, so the exact timing is not yet confirmed.
Frequently asked questions
Can I put the full £20,000 into one cash ISA?
Yes. The £20,000 adult allowance is one combined total, so you can put all of it into a single cash ISA in 2026/27 if you choose. Any amount you save in stocks and shares, innovative finance or Lifetime ISAs in the same year reduces what remains.
Will the cash ISA limit drop after April 2027?
For savers under 65, the cash ISA cap changes from 6 April 2027. You can pay at most £12,000 a year into cash ISAs in new deposits, and the other £8,000 of the allowance can go into stocks and shares ISAs or other eligible ISAs. Money already held in cash ISAs is not affected, and savers aged 65 and over keep the full £20,000 cash ISA limit (NS&I, 2026).
What happens to allowance I don’t use by 5 April 2027?
It is lost. Unused allowance does not carry over to the next tax year, so a new £20,000 allowance starts on 6 April 2027 regardless of how much you saved in 2026/27 (NS&I, 2026).
