What happens if you pay too much into an ISA?

What happens when you pay in too much?

The excess is removed from the ISA, along with any gains on it, and the rest of the ISA keeps its tax-free status. HMRC calls an ISA with an oversubscription “invalid”. Its rules say an ISA that is invalid only because the overall subscription limit has been exceeded can be repaired (regulation 4A of the ISA Regulations 1998).

HMRC’s guidance for providers says that after repair, “the balance of the account will remain exempt from tax”. The excess does not. It loses its ISA tax relief, and income earned on it can be taxed.

Paying in too much, at a glance

Overall ISA limit, 2026/27

£20,000

All your adult ISAs together

Lifetime ISA limit

£4,000

Counts inside the £20,000

The excess

Removed

From the ISA, with any related gains

Interest on the excess

Subject to tax

Counts towards your Personal Savings Allowance

Which payments do not use your allowance?

Check these before you assume you have paid in too much.

• A transfer. HMRC’s guidance says investments and cash transferred are not new subscriptions for the purposes of the overall subscription limit. It adds that payments you made in the same tax year and then transfer from one ISA to another are treated as if they were made to the receiving ISA. gov.uk says you can transfer all or part of your savings, made this year or in earlier years.
• A flexible ISA replacement. gov.uk says that if your ISA is flexible, you can take out cash then put it back in during the same tax year without reducing that year’s allowance. HMRC says money from earlier years can only be replaced in the account it came out of, and replacement money returned to a different account counts as a fresh subscription. Money taken out by a transfer to another provider, to cover fees and charges, or on HMRC’s instruction cannot be replaced without using allowance. See how a flexible ISA works.
• Holding several ISAs. Since 6 April 2024 you can pay into more than one ISA of the same type in a tax year, within the limits. The total is what counts. The exception is the Lifetime ISA, where you can pay into only one in a tax year.
• Special cases. HMRC lists additional permitted subscriptions (which a surviving spouse or civil partner can make), defaulted cash and investment subscriptions, and Help to Buy ISA reinstatement subscriptions as not counting towards the overall limit.

A withdrawal followed by a new payment is different. It is not a transfer. gov.uk says that if you withdraw the money without making a transfer, you will not be able to reinvest that part of your tax-free allowance again. Unless your ISA is flexible, HMRC says money that has left an ISA can only re-enter it as a fresh subscription, which counts towards the annual limit.

How does HMRC find out?

Your provider, you or HMRC can spot it. HMRC says a provider’s systems must make sure no more than the overall limit goes into the ISAs it manages for you. It also says a provider cannot know about ISAs you hold with other providers, and that individual investors remain responsible for managing their overall subscription limits.

HMRC can also find an oversubscription itself. Its guidance for providers says that if HMRC finds an oversubscription without being told, it informs the provider and the investor of the error and what action to take. In one of HMRC’s worked examples, the providers make their returns after the end of the tax year and HMRC then identifies the excess subscription. HMRC’s inspections of providers also include a check that subscription limits have not been exceeded.

What do your provider and HMRC do?

It depends on when the excess was paid in.

In the same tax year you paid in. HMRC’s guidance says the provider can tell you that the excess and any related gains will be removed. You tell it which payments to remove.

In an earlier tax year. HMRC’s guidance says the provider should tell you that HMRC will contact you. It says providers should not give advice, because they may not have all the relevant facts or be certain what action HMRC will take. HMRC may write to you first, and you have the chance to query the information provided to HMRC. If an ISA needs repair, HMRC sends the provider a notice of discovery and tells you what action the provider is to take. The date of the notice is the date of repair. The provider must follow the notice’s directions within 30 days (regulation 4A(5)).

What happens to the excess and its interest?

The excess stops being held in an ISA, and tax can be due on what it earned.

• The excess. HMRC says that from the date of repair the excess is not held in an ISA. In HMRC’s worked example, the provider removes the excess and pays it to the saver together with the interest earned on it. If the excess was in investments, the provider identifies the investments bought with it and removes them from the ISA within 30 days of the notice. In another example, the provider transfers some shares to the saver to hold outside the ISA.
• Tax relief. HMRC says all Income Tax and Capital Gains Tax relief on an oversubscription made in the tax year it is found, or in an earlier year, is lost up to the date of its repair letter.
• Interest. HMRC says all income earned on the excess before the repair notice is subject to tax, but only the income on the excess has to be removed from the ISA. Income removed from the ISA counts towards your Personal Savings Allowance or dividend allowance. gov.uk says you usually pay tax only on interest above your allowance. HMRC says providers have not deducted tax from this interest since 6 April 2016.
• Gains. For investments, HMRC says Capital Gains Tax will be applicable on any gains made when the assets are disposed of. With investments your capital is at risk.

An illustration. Someone pays £12,000 into a Cash ISA with one provider in June 2026, and £11,000 into a Cash ISA with another provider in February 2027. That is £23,000, so £3,000 is over the £20,000 limit. This is an example, not a real case.

Both payments fall in the same tax year, so the saver tells the providers which payment to remove. The £3,000 and any related gains then come out of that ISA. The other £20,000 is valid and keeps its tax exemption. Interest the £3,000 earned counts towards the saver’s Personal Savings Allowance.

What if a Lifetime ISA is involved?

HMRC’s rules treat a Lifetime ISA differently. Suppose you have gone over the overall limit but not the £4,000 Lifetime ISA limit. HMRC says the excess is then removed from your other ISAs in date order, even if you first paid into the Lifetime ISA later in the tax year. That way you keep the Lifetime ISA and do not pay its withdrawal charge.

If you went over the £4,000 limit itself, HMRC says the excess is removed from the Lifetime ISA without a withdrawal charge, and any government bonus paid on it must be returned to HMRC. If you pay into more than one Lifetime ISA in a tax year, the ISA Regulations say only one account is valid for a government bonus (regulation 4AA(4)). HMRC says the provider must contact HMRC for any Lifetime ISA repair.

What if you were not eligible to pay in?

Some invalid payments cannot be repaired. HMRC says an ISA is not eligible for repair if you did not meet the residence condition or were under age when you paid in. In those cases the provider must void the invalid payments. The payment and all income earned on it are removed from the ISA, and valid payments in earlier and later tax years are not affected. See who can open an ISA.

What should you do if you overpaid?

Work out the total, then tell your provider and, if you want to discuss it, HMRC. These steps describe the process, not advice on your own position.

1. Add up every payment into all your adult ISAs in the tax year, from 6 April to 5 April, and compare it with the £20,000 limit for 2026/27, or £4,000 for a Lifetime ISA. Leave out genuine transfers and flexible replacements, as above.
2. If you find it in the same tax year you paid in, tell your provider. HMRC’s guidance says the provider can remove the excess and related gains, and that you tell it which payments to remove.
3. If it was in an earlier tax year, expect HMRC to contact you. HMRC tells providers not to give advice on this, so contact HMRC if you want to discuss it. HMRC’s Income Tax enquiries page covers advice on savings, including ISAs.
4. Keep the details your provider gives you of interest or income paid on the excess, because it counts towards your allowances. HMRC tells providers to give investors the date and amount of each payment, and to say there may be more tax to pay.