Last updated: 6 October 2026 | Checked against GOV.UK and HMRC guidance for the 2026/27 tax year | Savings Accounts
If you pay more than £20,000 into ISAs in one tax year, the extra money is an invalid subscription and does not get ISA tax relief. If it happened in the current tax year, tell your ISA provider: under HMRC guidance the provider removes the excess and any related gains, and the rest of your ISA stays tax-free. If it happened in an earlier tax year, HMRC contacts you and tells the provider what to remove. Interest or income on the excess counts towards your Personal Savings Allowance or dividend allowance, so many people owe little or no tax.
A saver pays £4,000 into a Lifetime ISA in April, £12,000 into a cash ISA in June and £6,000 into a stocks and shares ISA in November. That is £22,000 in one tax year, so £2,000 is over the limit. Because the Lifetime ISA payment is within its own £4,000 limit, HMRC guidance says the excess comes out of the other ISAs, not the Lifetime ISA. The saver contacts the stocks and shares ISA provider, explains the error and asks for £2,000 and any related gains to be removed. The remaining £20,000 keeps its tax-free status.
Table of Contents
- ISA limits for 2026/27 and what counts towards them
- What happens if you go over your ISA limit
- Is there a penalty for paying too much into an ISA?
- Paid too much into an ISA: what to do
- Common ways people go over the limit
- How HMRC knows if you exceed your ISA allowance
- How to avoid going over your ISA allowance
- Frequently asked questions
Going over your ISA allowance is an easy mistake to make, especially now that you can pay into several ISAs of the same type in one tax year. It is also fixable. This guide explains what happens if you exceed your ISA allowance, what your provider and HMRC actually do, what tax can apply and the steps to take if you have paid too much into an ISA.
ISA limits for 2026/27 and what counts towards them
For the 2026 to 2027 tax year the most you can pay into ISAs is £20,000 in total. The tax year runs from 6 April to 5 April. You can put the whole amount into one account or split it across several, as GOV.UK explains.
| Limit | Amount in 2026/27 | What to know |
|---|---|---|
| Overall ISA allowance | £20,000 | Covers cash, stocks and shares, innovative finance and Lifetime ISAs added together. |
| Lifetime ISA | £4,000 | Counts as part of the £20,000. You can only pay into one Lifetime ISA in a tax year. |
| Number of ISAs you can pay into | No set number | You can pay into more than one ISA of the same type in a tax year, for example two cash ISAs, as long as the total stays within £20,000. |
| Unused allowance | Lost on 5 April | You cannot carry unused allowance forward into the next tax year. |
The limit applies to new money you pay in during the tax year. It does not apply to the balance. These do not use up your allowance:
- Interest, dividends and investment growth earned inside the ISA.
- Money moved between providers using a proper ISA transfer.
- Money you take out and put back into a flexible ISA in the same tax year. See the GOV.UK withdrawal rules.
So you can hold £40,000, £100,000 or more in ISAs built up over several years. What you cannot do is pay in more than £20,000 of new money in one tax year. If you are unsure how many accounts you can use, see how many cash ISAs you can have and when the ISA allowance resets.
What happens if you go over your ISA limit
Money paid in above the limit is treated as an invalid subscription. It is not entitled to ISA tax relief, and it has to come out of the ISA. What happens next depends on which tax year the mistake was made in. This is set out in HMRC guidance on repairing an ISA.
| When you went over | Who acts | What happens |
|---|---|---|
| Current tax year | Your ISA provider | Once you tell them, the provider can remove the excess and any related gains to correct the error. You tell them which payments to remove. The valid payments keep their tax exemption. |
| A previous tax year | HMRC, then your provider | The provider should tell you HMRC will contact you. HMRC may write to you first, gives you the chance to query the figures, then issues a notice telling the provider what to remove. |
| Any year, involving a Lifetime ISA | Your provider and HMRC | The provider must contact HMRC for all Lifetime ISA repairs. |
Fixing the account this way is called a repair. After a repair the excess is taken out and the rest of the ISA carries on tax-free. Only if an ISA cannot be repaired is it made void, which means the invalid payment and all the income earned on it are removed. Payments made validly in other tax years are not affected.
HMRC guidance says that for previous years, invalid investments lose their tax exemption from the date of the first invalid payment up to the date of repair. The longer an excess sits in the account, the more interest or growth ends up taxable. A current-year mistake that you report quickly usually involves very little.
Is there a penalty for paying too much into an ISA?
HMRC guidance on excess subscriptions describes lost tax relief, not a fixed fine. The cost of going over the limit is that the excess is treated like money held outside an ISA for the period it was invalid:
- Interest or income removed from the ISA counts towards your Personal Savings Allowance or dividend allowance. If you are within those allowances there may be no tax to pay on it.
- Capital Gains Tax can apply to gains made when investments bought with the excess are sold.
- For a Lifetime ISA, any government bonus paid on an excess payment must be returned to HMRC.
Providers are required to tell you that there may be more tax to pay. If HMRC decides tax is due it will tell you how it will be collected. You can check how savings interest is taxed with our savings interest calculator.
A small overpayment is rarely expensive. £500 too much in a cash ISA paying 4% earns about £20 in a year. For a basic rate taxpayer with unused Personal Savings Allowance, that interest would normally fall within the £1,000 allowance.
Paid too much into an ISA: what to do
- Add up every payment for the tax year. List each ISA, the date and the amount. Leave out transfers between providers and interest, as they do not count.
- Work out the excess and where it sits. The excess is normally the most recent payment or payments that took you over £20,000. If a Lifetime ISA is involved and you stayed within its £4,000 limit, the excess comes out of your other ISAs.
- Contact the provider before moving money yourself. Say that you have exceeded the overall subscription limit and ask them to remove the excess. For a current-year error they can do this and will ask which payments to remove.
- Do not just withdraw the money and assume it is fixed. In an ISA that is not flexible, a normal withdrawal does not give you allowance back. Ask the provider to remove it as an excess subscription so the error is corrected on their records.
- If the mistake was in an earlier tax year, wait for HMRC. Providers are told not to repair a previous-year error until HMRC issues its notice. Reply promptly when HMRC writes, and check its figures.
- Speak to HMRC if you want to discuss it. HMRC guidance says investors can use the Income Tax general enquiries helpline on 0300 200 3300.
- Keep the paperwork. Save the provider confirmation and any HMRC letter with your tax records.
Common ways people go over the limit
Paying into several ISAs and losing track
You are allowed to pay into more than one ISA of the same type in a tax year, so two cash ISAs are not a problem in themselves. The problem is the combined total. Each provider only sees its own account. HMRC guidance states that providers do not need to establish what you have paid in elsewhere, and that keeping within the overall limit is your responsibility.
Paying more than £4,000 into a Lifetime ISA
If you stay within £20,000 overall but put more than £4,000 into a Lifetime ISA, the Lifetime ISA itself has to be repaired. The excess is removed without the usual withdrawal charge because it was never a valid payment, and any bonus paid on it goes back to HMRC. You can also only pay into one Lifetime ISA in a tax year. More detail is in our guide to the Lifetime ISA withdrawal charge.
Taking money out and paying it back in
With a flexible ISA you can replace money you withdrew in the same tax year without it counting again. With an ISA that is not flexible, anything you pay back in counts as a new payment. GOV.UK gives the example of paying in £10,000 and withdrawing £3,000: you can then pay in £13,000 more if the ISA is flexible, but only £10,000 if it is not. Ask your provider which type you have.
Moving an ISA yourself
Closing one ISA and paying the money into another is not a transfer. The money leaves the ISA wrapper and the new payment uses up allowance. To switch provider, ask the new provider for an ISA transfer form so the money moves directly.
Payments around 5 April
A payment counts towards the tax year in which it reaches the ISA. Standing orders and late transfers that land on or after 6 April use the new year’s allowance, and one that lands earlier than planned can push the old year over.
Inherited ISA allowance
If your spouse or civil partner has died you may be able to pay in extra on top of your own allowance, up to the value of their ISA. This is a separate entitlement and does not count as going over the limit. Ask the provider about additional permitted subscriptions.
How HMRC knows if you exceed your ISA allowance
You give your National Insurance number when you open an ISA, and ISA providers send HMRC returns of information that include the payments made into each account. HMRC can therefore add up what one person has paid in across all providers. Under HMRC guidance on ISA subscriptions, if HMRC finds an oversubscription that nobody reported, it informs both the provider and the investor and says what action to take.
This check happens after the tax year has ended, so a letter can arrive long after the payment was made. Telling your provider as soon as you spot the error is quicker and limits how much interest or growth becomes taxable.
How to avoid going over your ISA allowance
- Keep one running total of new payments for the tax year across every ISA, including any Lifetime ISA.
- Check regular payments and standing orders before adding a lump sum.
- Use the transfer process to move money between providers and never withdraw and repay to switch.
- Confirm whether each ISA is flexible before taking money out with the plan of putting it back.
- Leave a small margin below £20,000 if you make many small payments.
- Review your plan each April. See our guide to the ISA allowance for 2026/27.
One change to plan for: under the reforms announced at the Autumn Budget 2025, from 6 April 2027 savers under 65 will be limited to £12,000 a year in cash ISAs within the £20,000 overall allowance. That creates a second limit that can be breached by cash savers. Our guide to the cash ISA rule changes explains what is changing.
MoneyWise UK checked this guide against GOV.UK and HMRC guidance for ISA managers on 6 October 2026. It is general information only, not personalised financial or tax advice. Rules and provider terms can change, so check the linked official sources before acting.
- The limit is £20,000 of new money across all your ISAs in 2026/27, with £4,000 of that available for a Lifetime ISA.
- Money paid in above the limit is invalid and has to be removed. The rest of your ISA stays tax-free.
- Current tax year: tell your provider, who removes the excess and related gains.
- Previous tax year: HMRC contacts you and instructs the provider.
- There is no fixed fine in HMRC guidance. Income on the excess becomes taxable and counts towards your savings or dividend allowance.
- Transfers, interest and flexible ISA replacements do not count towards the limit.
- GOV.UK: Individual Savings Accounts
- HMRC: Manage ISA subscriptions
- HMRC: Close, void or repair an ISA
Rules, rates and provider terms may change. Check official sources before making financial decisions.
Before you act: savings checks
Use this section as a final check before applying, claiming, switching, transferring money or relying on a figure. Rules, rates and provider terms can change, so verify the current position with the linked official sources.
| Decision point | What to check | Source to verify |
|---|---|---|
| Tax position | Check Personal Savings Allowance, ISA allowance and whether interest will be taxable for your circumstances. | GOV.UK: tax on savings interest GOV.UK |
| Access | Compare withdrawals, notice periods, maturity rules, penalties and whether the rate is fixed or variable. | GOV.UK: Individual Savings Accounts Provider terms |
| Protection | Check FSCS or NS&I protection and whether brands share one banking licence. | FSCS: deposit protection FSCS / NS&I |
- Monthly Interest Savings Accounts UK 2026: Best Rates and Who They Suit
- Fixed Rate Bond vs Cash ISA: Which Pays More After Tax in 2026/27?
- Cash ISA Rule Changes 2026: What the New Limits Mean for Your Savings
- Claiming Premium Bonds After a Death in 2026: What to Do When NS&I Delays Your Payout
- Junior ISA vs Savings Account: Which Is Better for Your Child’s Money in 2026?
Frequently Asked Questions
What happens if I put too much money into my ISA?
The amount above £20,000 is an invalid payment and does not qualify for ISA tax relief. If it was paid in the current tax year, your provider can remove the excess and any related gains once you tell them. If it was in an earlier tax year, HMRC contacts you and instructs the provider. The rest of your ISA keeps its tax-free status.
What should I do if I have paid too much into an ISA?
Add up all new payments for the tax year, work out the excess, then contact the provider holding it and ask them to remove the excess subscription. Avoid simply withdrawing the money yourself, because a normal withdrawal from an ISA that is not flexible does not restore allowance. For an earlier tax year, wait for HMRC to write to you.
Is there a fine for going over the ISA limit?
HMRC guidance on excess ISA payments does not set out a fixed fine. The consequence is lost tax relief: interest or income on the excess counts towards your Personal Savings Allowance or dividend allowance, and Capital Gains Tax can apply to gains. Many people with a small overpayment owe little or nothing.
How does HMRC know if you exceed your ISA allowance?
ISA providers send HMRC returns of information showing what has been paid into each account, linked to your National Insurance number. HMRC can total these across providers. If it finds an oversubscription, it informs you and the provider and says what must be done.
What happens if I accidentally pay into two ISAs in one tax year?
Paying into two ISAs of the same type in one tax year is allowed, so this alone is not a breach. It only matters if the combined payments exceed £20,000, or if you pay into more than one Lifetime ISA in the same tax year.
Can I have more than £20,000 in my ISA?
Yes. The £20,000 limit is on new money paid in during a single tax year, not on the balance. Savings built up over several years, plus interest and investment growth, can take your ISAs well above £20,000.
Can I pay £20,000 into an ISA every year?
Yes. You get a new allowance each tax year on 6 April. Unused allowance cannot be carried forward, so anything you do not use by 5 April is lost.
What if I go over the Lifetime ISA limit of £4,000?
The Lifetime ISA has to be repaired and the excess removed. Because the excess was never a valid payment it comes out without the withdrawal charge, and any government bonus paid on it is returned to HMRC. Your provider must contact HMRC for Lifetime ISA repairs.
MoneyWise UK provides information for general guidance only. This is not financial advice. Always consult a qualified financial adviser before making major financial decisions.
