Key takeaways
- The 2026 to 2027 ISA allowance is £20,000 across all adult ISAs, of which at most £4,000 can go into a Lifetime ISA. Junior ISAs sit outside it, at £9,000.
- Pay £10,000 into a flexible ISA and take £3,000 out, and you can still add £13,000 this tax year. In a non-flexible ISA the figure is £10,000.
- Moving provider by withdrawing the money destroys that allowance permanently. A provider-to-provider transfer does not, and cash-to-cash transfers are capped at 15 working days.
- Since 6 April 2024 you can pay into more than one ISA of the same type in a year. The Lifetime ISA is the exception, at one account and £4,000.
- An ISA stays tax-free for 3 years and 1 day after death, and a surviving spouse gets extra allowance equal to its value, on top of their own £20,000.
The allowance is £20,000. The rules that cost you money sit underneath it.
You want to know how much you can put into an ISA this year, and what happens if you take some of it back out. For the 2026 to 2027 tax year, GOV.UK answers the first half in one line: "In the 2026 to 2027 tax year, the maximum you can save in ISAs is £20,000". Junior ISAs are separate, with their own limit of £9,000 for the same year.
That's the number every explainer stops at, and it's the number that costs almost nobody anything. The rules that do cost money sit underneath it. Whether your account is flexible. How you move it to another provider. How many accounts you're allowed to feed. What happens to the wrapper when you die.
Here's the short answer to all four. A flexible ISA lets you put back what you took out, in the same tax year, into the same account. Moving provider by withdrawing the cash yourself burns that part of the allowance for good. You can now pay into several ISAs of the same type in one year, but only ever one Lifetime ISA. And an ISA doesn't end when you do — it keeps its tax treatment for up to 3 years and 1 day, and a surviving spouse inherits its value as extra allowance on top of their own.
The chart above shows the limits themselves, including the split that arrives in April 2027. Everything else in this piece is about the machinery those limits sit on.
A flexible ISA replaces cash, and only into the account it came out of.
"Flexible" is a legal feature with a definition, not a marketing adjective. HMRC's guidance for ISA managers calls it an ISA "whose terms and conditions allow the investor to replace, in whole or in part, cash they have withdrawn, without the replacement counting towards their annual subscription limit".
GOV.UK's own worked example is the clearest statement of what that's worth. Your allowance is £20,000 and you pay in £10,000. You then take out £3,000. What you can pay in for the rest of that tax year is "£13,000 if your ISA is flexible" and "£10,000 if your ISA is not flexible". Same balance, same withdrawal, and £3,000 of difference in what you can still shelter.
Four things narrow that benefit, and none of them tend to appear on a product page.
Flexibility is optional. HMRC says so in one sentence: "Offering flexibility is optional for ISA managers". Lifetime ISAs and Junior ISAs can't be offered as flexible at all, so the feature simply doesn't exist there.
The money has to go back where it came from. HMRC tightened the wording in 2024 to remove any doubt: "The withdrawal of previous year funds from a flexible ISA can only be replaced in the account from where the withdrawal was made and must be replaced in the same tax year". Take previous-year money out in February and you can't replace it through a different provider, and you can't replace it after 5 April.
Only cash is flexible. HMRC is explicit that "Flexibility can be offered in respect of cash only", covering cash ISAs and cash held inside a stocks and shares ISA. Shares can't be taken out and put back.
And a whole list of things that look like withdrawals can't be replaced without eating the allowance. HMRC names them: a transfer to another provider, a removal by HMRC to cover a tax debt, a withdrawal on the authority of a court order, and — the one that catches people quietly — money taken out "to cover fees and charges". If your platform bills its annual charge by selling units inside the ISA, those pounds have left the wrapper and the flexibility rules don't bring them back. That's a small annual leak sitting on top of the ones in our piece on what platform fees, FX spreads and withholding tax actually cost.
Flexibility matters most where money genuinely moves in and out during a year, which in practice means cash rather than investments. That's the same design question our piece on where emergency cash sits, and what liquidity costs in yield works through from the other direction.
Transferring by withdrawal destroys allowance. The transfer form doesn't.
This is the most expensive avoidable mistake in the system, and GOV.UK states the consequence in a single sentence: "If you withdraw the money without doing this, you will not be able to reinvest that part of your tax-free allowance again".
The mechanism is dull and absolute. Money moved between managers on a transfer instruction is not a new subscription, so it doesn't touch this year's £20,000. The same money handed to you first is a withdrawal. HMRC's manager guidance puts it to the outgoing provider directly: "If you transfer them to the investor, this will be treated as a withdrawal, so the investments and cash will lose their tax-free wrapper".
Put numbers on it. Someone with a cash ISA built up over a decade who closes it, receives the cash, and pays it into a better-paying account elsewhere has converted a wrapper of any size into a single subscription capped at £20,000. Everything above that line is now taxable savings, and there's no carry-forward to fall back on. HMRC's guidance confirms that an investor "who has not subscribed up to the limit in any year cannot carry forward the difference".
The transfer route has deadlines attached. GOV.UK gives them as "15 working days for transfers between cash ISAs" and "30 calendar days for other types of transfer". HMRC's manager guidance breaks the first one down: the new manager has 5 business days to forward the instruction, the old manager has 5 to send the funds, the new manager has 3 to apply them, and 2 are allowed for post.
Two details are worth knowing before you start one. You can transfer part of a balance rather than all of it, and you can transfer to a different type of ISA — GOV.UK: "It can be to a different type of ISA or the same type. The investment can have been made this year or in previous years". And a flexible ISA loses something in transit. HMRC: "Where a flexible ISA is transferred with 'net' current year subscriptions of £nil the ability to replace any current year income withdrawn prior to the transfer will be lost".
You can pay into more than one ISA of the same type, but only since 6 April 2024.
For years the rule was one cash ISA and one stocks and shares ISA per tax year. That's the rule most people still carry around, and it's out of date. HMRC's own change log for the transfer manual records the switch on 6 April 2024: "Investors can now open multiple ISAs of the same type in the same tax year".
GOV.UK now teaches the new position with a worked example: "You could save £10,000 in one cash ISA, £3,000 in another cash ISA and £7,000 in a stocks and shares ISA in one tax year". Chasing a better fixed rate in October no longer means waiting for April.
The Lifetime ISA is carved out. GOV.UK: "You can only pay into one Lifetime ISA in a tax year. The maximum you can pay in is £4,000 in a tax year". That £4,000 comes out of the same £20,000, and it buys a bonus — "The government will add a 25% bonus to your savings, up to a maximum of £1,000 per year". It also comes with an exit price. Take the money out for anything other than a first home costing £450,000 or less, terminal illness, or reaching 60, and there's a 25% withdrawal charge. GOV.UK's example is worth reading twice: £800 saved plus a £200 bonus makes £1,000, and withdrawing the lot leaves £750.
Two age lines are easy to miss. You must be 18 or over to open an adult ISA, and under 40 to open a Lifetime ISA. And "When you turn 50, you will not be able to pay into your Lifetime ISA or earn the 25% bonus".
The freedom to hold several accounts moves the policing onto you. HMRC tells managers the opposite of what most savers assume: "Managers do not need to establish the amount subscribed to ISAs held with other managers. Investors who subscribe to ISAs held with different managers are responsible for ensuring that they do not exceed the overall subscription limit". Split £20,000 across four providers and no single one of them can see the total.
Death doesn't close the wrapper, and a spouse inherits the value as extra allowance.
An ISA does not stop being an ISA on the day the holder dies. GOV.UK: "Otherwise, your ISA provider will close your ISA 3 years and 1 day after you die". HMRC's manager guidance sets the same clock from the other end — the tax advantages run until the earlier of the completion of the estate's administration, "the day falling on the third anniversary of the death", or the closure of the account. In the meantime the account is a "continuing account of a deceased investor": still tax-free inside, no new payments in, and still counted in the estate for Inheritance Tax.
Then there's the part that surprises people. A surviving spouse or civil partner gets an extra allowance equal to the deceased's ISA. GOV.UK: "As well as your normal ISA allowance you can add a tax-free amount up to either: the value they held in their ISA when they died [or] the value of their ISA when it's closed". Whichever is higher. That sits on top of the survivor's own £20,000, and it doesn't depend on inheriting the actual money — HMRC's guidance says the subscriptions "are available whether or not the surviving spouse or civil partner inherited the deceased's ISA assets".
The conditions are strict, and they're where this goes wrong. The couple must have been living together at the date of death, and not separated under a court order, a deed of separation, or in circumstances where the relationship has broken down. Unmarried partners get nothing. Managers aren't obliged to accept the subscriptions at all.
The clock is generous but finite. HMRC: "The time limit for making cash subscriptions ends 3 years after the date of death, or if later, 180 days after the administration of the estate is complete". Transferring the actual investments across rather than selling them is tighter — that has to happen "within 180 days of the distribution of the assets to the surviving spouse or civil partner", and it's only available with the manager who held the deceased's ISA.
One trap sits inside the choice of provider. Once the survivor starts using the allowance somewhere, it's locked there. HMRC: "Where an additional permitted subscription is made, any further payments up to the limit must be made with the same manager. Any unused balance cannot be used with another manager".
The strongest objection: for most savers the allowance was never the constraint.
There's a serious case that all of this is a minority sport, and HMRC's own statistics make it. In the 2022 to 2023 tax year, "22.7% of the total subscribers saved at the maximum". The largest group did nothing of the kind: "The highest proportion of savers, around 41.9%, saved between £1 and £2,499".
For a saver whose subscription sits in that £1 to £2,499 band, flexibility changes nothing, because the allowance was never going to bind. Withdrawing to switch provider costs them nothing either, since the same money fits back inside a fresh subscription. The transfer form is administrative housekeeping, not a tax event.
The objection is right, and it's also narrower than it looks. The same statistics show 59.9% of subscribers with income of £150,000 or more saved the maximum, against 40.5% of those on £100,000 to £149,999 — so the people the rules bite are exactly the people with the largest balances. At the end of the 2023 to 2024 tax year the market value of adult ISA holdings stood at £872 billion, and most of that is previous-year money that a mishandled transfer would strip of its wrapper regardless of how much the holder is paying in now. The death rules are more indiscriminate still. They apply to anyone with a spouse and an ISA, at any balance, and the 180-day in-specie window closes whether or not the family knows it exists.
The honest summary of the counter-argument is that these rules are worth reading in proportion to what's already inside the wrapper, not in proportion to what you're adding this year. Someone whose ISA is worth about £8,288 — the average for an under-25 holder — can skip most of this. Someone in the 65-and-over group, where the average holding is £64,386, can't.
What these rules cannot tell you.
Start with the limitations of the source material. Everything above is HMRC's published guidance for the 2026 to 2027 tax year, not the regulations themselves — the guidance summarises the Individual Savings Account Regulations, and where the two ever diverge, the regulations win. Guidance also changes without a headline. The flexible ISA replacement rule was clarified twice, in April 2024 and again in 2025, which is why writing this from memory produces the wrong answer.
These are UK rules, and they follow tax residence, not nationality. If you leave the UK you can keep an ISA and keep the tax relief, but you can't subscribe to it while non-resident unless you're a Crown employee or their spouse.
The rules also cannot tell you the thing you probably want to know. They set what's permitted, not what's worth doing. Nothing in the ISA regulations has an opinion on whether your £20,000 belongs in cash or in equities, and the wrapper's value depends entirely on there being tax to save. Where it does have value, it compounds the same way a fee does, in reverse — the arithmetic is the one laid out in our piece on how fund fees compound over decades.
And the statistics have their own vintage problem. HMRC's income and subscription breakdowns run to the 2022 to 2023 tax year, which is before the multiple-ISA change took effect, so they can't yet show whether savers are using it.
What would change this: 6 April 2027.
The single-allowance story is about to end. At Autumn Budget 2025 the government announced that from April 2027 the cash ISA allowance falls to £12,000 for savers under 65, while the overall limit stays at £20,000. HMRC's June 2026 factsheet confirms the start date as 6 April 2027, and confirms that anyone aged 65 or over keeps a cash limit of £20,000, from the start of the tax year in which they turn 65.
Two supporting rules matter more than the headline. A flat-rate charge of 22% applies to interest paid on cash held inside a stocks and shares or innovative finance ISA, which closes the obvious workaround. And transfers run one way only: transfers from non-cash ISAs into cash ISAs are not permitted, though cash to non-cash still is. For anyone whose plan involves parking a full allowance in an investment account and moving it to cash later, that door shuts. Draft legislation is out for technical consultation, with regulations due to be laid in the autumn.
There's a second consultation running alongside it, closing in August 2026, on a simpler first-time buyer product that would be offered in place of the Lifetime ISA. Existing Lifetime ISAs would carry on under the current rules.
Knowing your remaining allowance is a record-keeping problem before it's a tax problem, and it gets harder the moment you hold several accounts of the same type. LedgerTouch keeps the contribution dates and amounts in one place; a dated spreadsheet does the same job.
The thing to watch isn't the allowance. It's the two questions no product page answers: whether your provider's terms actually offer flexibility, and whether the wrapper you're building can still be moved where you want it after April 2027. The first is a line in the terms and conditions. The second is now a policy question, and the answer changed once already.