If you pay more into ISAs in a tax year than the allowance, the extra isn’t a valid ISA payment. It doesn’t make your whole ISA invalid: the excess is taken out, and the rest of the account stays tax-free. How it’s fixed depends on when the mistake is found.
What happens
If you pay in more than the ISA allowance, the excess isn't a valid ISA subscription: in the current tax year your provider can remove it and any related gains; for past years HMRC contacts you and tells your provider what to take out. Tax relief on the excess is lost, and the rest of the ISA stays tax-free.- In the current tax year, tell your provider: it can remove the excess and any related gains, following your instructions on which payments to take out.
- For an earlier tax year, HMRC will contact you, and then tells your provider what to do.
- Tax relief on the excess is lost up to the date of the repair; after the excess is removed, the rest of the ISA stays tax-free.
- Income removed from the ISA counts towards your Personal Savings Allowance or dividend allowance, and gains can be liable to Capital Gains Tax.
- Paying more than the Lifetime ISA limit: the excess is removed without the withdrawal charge, and any bonus paid on it goes back to HMRC.
- An ISA opened while not UK resident or under age can't be repaired: those subscriptions are made void.
If you spot it in the same tax year
Contact your ISA provider and tell it you’ve gone over. It can remove the excess and any gains on it, and you tell it which payments to take out. The earlier you catch it, the less the excess will have earned, and the less there is to be taxed.
If it’s from an earlier tax year
Your providers report what you’ve paid in to HMRC each year, so HMRC may find an overpayment itself. HMRC contacts you, and then tells your provider what to remove; you can give HMRC your side of it before that happens. Your provider shouldn’t try to repair a past-year overpayment without HMRC’s instruction. If you’d rather raise it yourself, you can call HMRC’s Income Tax helpline.
How overpayments usually happen
- Paying into more than one ISA without adding them up, for example a cash ISA with one bank and a stocks and shares ISA with a platform.
- Withdrawing and paying back into an ISA that isn’t flexible. Money you put back counts as a new payment: see flexible ISAs.
- Moving an ISA by withdrawing and reopening instead of using an ISA transfer. The money going into the new ISA counts as a new payment.
- Forgetting a Lifetime ISA. Its payments count towards the overall allowance as well as its own £4,000 limit.
- From 6 April 2027, paying more than £12,000 into cash ISAs if you’re under 65, even when your total is within the overall allowance (the cash ISA limit).
How to avoid it
Keep a note of every payment into an ISA from 6 April, across all your providers. Only new money paid in counts: interest, growth and ISA transfers don’t. If you’re close to the limit, check with each provider what it has recorded before paying in more.
Related guides
- ISA allowance: how much you can pay in, and splitting it
- Flexible ISAs: taking money out and putting it back
- ISA transfers: moving an ISA without it counting as a new payment
- ISAs guide: the ISA types, the allowance and the main choices in one place