What is the annual ISA allowance?

The overall adult ISA allowance is £20,000 per tax year (6 April to 5 April). You can split it across Cash, Stocks & Shares, Lifetime and Innovative Finance ISAs in any combination, but your total subscriptions cannot exceed £20,000.

How does the Lifetime ISA sub-limit work?

You can pay at most £4,000 into a Lifetime ISA each tax year, and that £4,000 counts towards your overall £20,000 allowance. The government adds a 25% bonus on LISA contributions, so £4,000 earns a £1,000 bonus.

Is the Junior ISA part of the £20,000?

No. The Junior ISA has its own separate £9,000 annual allowance and does not count towards the adult £20,000. A child's JISA is funded by parents or others, and the £9,000 is shared across the child's Cash and Stocks & Shares JISAs.

Can I pay into more than one ISA of the same type?

Since the 2024/25 tax year you can open and pay into multiple ISAs of the same type in one year (except Lifetime ISAs), as long as your combined subscriptions stay within the £20,000 overall allowance.

Does unused allowance carry over?

No. The ISA allowance is use-it-or-lose-it for each tax year. Any part of the £20,000 you do not subscribe by 5 April is lost — it does not roll forward into the next year.

UK ISA Annual Allowance Calculator

A UK ISA allowance calculator that keeps your tax-free savings within the rules. It tracks the £20,000 annual adult allowance across Cash, Stocks & Shares and Lifetime ISAs, enforces the £4,000 Lifetime ISA sub-limit (and shows its 25% government bonus), and accounts for the entirely separate £9,000 Junior ISA allowance for a child’s account.

How it works

All adult ISA subscriptions share one £20,000 pot. The Lifetime ISA is special: it has its own £4,000 ceiling, but that money still counts inside the £20,000:

lisaUsed   = min(lisaPaid, 4000)            (LISA capped at £4,000)
lisaBonus  = lisaUsed * 0.25                (25% government bonus)
adultUsed  = cash + stocks + lisaUsed
remaining  = max(0, 20000 - adultUsed)

Junior ISA is separate:
jisaUsed      = min(cashJisa + stocksJisa, 9000)
jisaRemaining = max(0, 9000 - jisaUsed)

The tax year runs 6 April to 5 April and the allowance is use-it-or-lose-it — anything unused by 5 April is gone. If you pay more than £4,000 into a Lifetime ISA the excess is invalid, and the tool flags it. Junior ISA contributions never touch the adult £20,000.

Example and notes

Pay £8,000 into a Cash ISA, £6,000 into Stocks & Shares, and £4,000 into a Lifetime ISA: that is £18,000 of the adult allowance used, leaving £2,000 of tax-free room, and the LISA has earned a £1,000 government bonus. Separately, £5,000 into a child’s Junior ISA leaves £4,000 of the £9,000 JISA allowance.

Figures reflect the current £20,000 / £4,000 / £9,000 limits. The 25% LISA bonus is paid on contributions (and there are rules and charges on early withdrawal for non-qualifying reasons). All calculations run locally in your browser.