ISA allowance calculator
How much of the £20,000 allowance you have used, what is left, and what you would need to put in each month to use it all before 5 April.
How this is calculated
The £20,000 allowance is shared across every type of ISA. Splitting money between a cash ISA and a stocks and shares ISA does not give you two allowances.
The Lifetime ISA has its own £4,000 sub-limit inside that £20,000, and attracts a 25% government bonus on whatever you pay in, up to £1,000 a year.
The allowance runs from 6 April to 5 April and does not carry over. Anything unused on 5 April is gone.
The monthly figure divides what is left by the months remaining, which is usually a more useful number than the total when you are deciding what to do about it.
Rates used · 2026/27
| Total ISA allowance | £20,000 |
| Lifetime ISA limit | £4,000, inside the £20,000 |
| Lifetime ISA bonus | 25%, up to £1,000 a year |
| Tax year | 6 April to 5 April, no carry over |
| Cash ISA from April 2027 | £12,000 for under-65s |
Last checked July 2026. Source: HMRC and gov.uk.
Worked example
With £6,000 in a cash ISA and £3,000 in a stocks and shares ISA, you have used £9,000 of the £20,000 allowance. That leaves £11,000, and with six months to go that is £1,833 a month to use it all before 5 April. Anything left on 5 April is gone.
Common questions
Can I have more than one ISA?
Yes, and since 2024 you can pay into more than one of the same type in a tax year. The £20,000 total still applies across all of them.
Does the allowance carry over?
No. Anything unused on 5 April is lost, which is why the run-up to the deadline is so busy.
What is changing in April 2027?
The cash ISA limit drops to £12,000 a year for under-65s, while the overall £20,000 allowance stays. The remaining £8,000 would have to go into stocks and shares, innovative finance or a Lifetime ISA. Over-65s are unaffected.
Does a withdrawal free up allowance?
Only in a flexible ISA, where money taken out and replaced in the same tax year does not use the allowance twice. Not every provider offers this, so check.