Free UK Tool · 2025/26 Allowances

ISA Calculator

Model the tax-free growth of a Cash ISA, Stocks & Shares ISA, or Lifetime ISA. Includes the 25% government LISA bonus and a full year-by-year breakdown.

Lifetime ISA rules: max £4,000/year contribution (£333/month) — contributions above this are capped in the calculation. The government adds a 25% bonus monthly, up to £1,000/year. You must be aged 18–39 to open a LISA. Use for a first home purchase (≤ £450,000) or retirement from age 60.
Stocks & Shares ISA: returns are not guaranteed. The growth rate you enter is an assumption, not a prediction. Historical global equity returns have averaged around 7% per year over the long term, but your actual returns may be higher or lower.
Final ISA Value
Tax-free
Total Contributed
Your money
Total Growth
Tax-free earnings
Government Bonus
Total Bonus Received
Bonus as % of Contributions
Year-by-Year Breakdown
Year Contributions Growth Balance

Which ISA Is Right for You?

All ISAs share the same core benefit: any interest, dividends, or capital gains earned inside the wrapper are completely tax-free. The differences lie in how the money is invested, what the government contributes, and what conditions apply to withdrawals.

Cash ISA

A Cash ISA works like a normal savings account but within a tax-free wrapper. Your balance is protected and cannot fall. They're ideal for short-to-medium term goals, emergency funds, or money you can't afford to risk. Balances up to £85,000 are protected by the FSCS.

Stocks & Shares ISA

A Stocks & Shares ISA invests your money in the market — typically funds, shares, or bonds. Over the long term (10+ years), equities have historically delivered higher returns than cash, but the value can fall as well as rise. They're suited to long-term goals where short-term fluctuations can be absorbed.

Lifetime ISA (LISA)

The LISA is arguably the best savings product available to those who qualify. You must be aged 18–39 to open one. The government adds 25% on top of everything you contribute (up to £1,000/year bonus on a £4,000 contribution). It can be used tax-free for a first home purchase (property must cost £450,000 or less) or from age 60 for retirement. Withdrawing for any other reason incurs a 25% penalty, which claws back the bonus and a small portion of your own money.

Annual ISA Allowance

The annual ISA allowance for 2025/26 is £20,000 across all ISA types combined. The £4,000 LISA limit counts within this total. You can split your allowance between multiple ISAs of different types in the same tax year.

Frequently Asked Questions

The annual ISA allowance is £20,000. This can be split across a Cash ISA, Stocks & Shares ISA, Innovative Finance ISA, or Lifetime ISA (LISA) in the same tax year, as long as the total across all accounts does not exceed £20,000. The LISA has its own sub-limit of £4,000 per year.
The government adds a 25% bonus to every pound you put into a Lifetime ISA, up to a maximum of £1,000 per year (on £4,000 of contributions). The bonus is paid monthly by HMRC. You must be aged 18–39 to open a LISA and can continue contributing and receiving the bonus until you turn 50.
You can withdraw penalty-free to buy your first home (property must cost £450,000 or less, and you must have held the LISA for at least 12 months) or from age 60 for retirement. Any other withdrawal triggers a 25% government penalty charge, which effectively returns the bonus and removes a small portion of your own contributions.
A Cash ISA earns interest at a fixed or variable AER. Your balance is protected and guaranteed not to fall, making it lower risk. A Stocks & Shares ISA invests in the market and aims for higher long-term returns, but the value can go down as well as up. Both are completely tax-free wrappers — no tax on interest, dividends, or capital gains inside the account.
Yes. Since April 2024 you can open and pay into multiple ISAs of the same type in the same tax year, as long as your total contributions across all ISAs don't exceed the £20,000 annual allowance. Previously, you were limited to one of each type per year.