Lifetime ISA Calculator

A Lifetime ISA (LISA) gives you a 25% government bonus on up to £4,000 a year - up to £1,000 of free money - to put towards your first home or retirement. This calculator projects your pot, including the bonus and any investment growth, year by year.

This Lifetime ISA calculator shows you exactly how much your savings could grow once the 25% government bonus and any interest or investment returns are added in, year by year, so you can plan a first home deposit or a retirement pot with real numbers rather than guesswork. Enter what you intend to pay in, choose your time horizon, and the tool works out your contributions, your bonuses and your projected pot in seconds.

What this Lifetime ISA calculator does

A Lifetime ISA (LISA) is generous but the maths is easy to get wrong, because the bonus is paid on contributions rather than on your balance, it is capped each year, and your own money can also grow on top. This tool brings all of that together. Acting as a LISA bonus calculator and a longer-term projection tool at the same time, it tells you:

• The 25% government bonus you will earn on your contributions, year by year and in total.
• How much of your final pot is your own money, how much is free bonus, and how much is growth.
• Your projected lifetime ISA growth over the number of years you plan to save.
• How close your contributions sit to the 4,000 annual limit and the 1,000 maximum bonus.

It is built specifically around the UK LISA rules, so it will not let the bonus run away beyond the annual cap, which is a common mistake when people try to model a Lifetime ISA in a basic spreadsheet.

How to use the calculator, step by step

The calculator above is designed to be quick. Here is how to get the most accurate result:

1. Enter your contribution. Put in either a monthly amount (for example 200 a month) or an annual figure. The tool caps the bonus-eligible amount at 4,000 per tax year automatically.
2. Add any existing balance. If you already have a Lifetime ISA, enter the current pot so future bonuses and growth build on what you have.
3. Choose your time horizon. Set how many years you plan to keep saving. For a first home this might be three to five years; for retirement it could be 20 or more.
4. Set an expected growth rate. For a cash LISA, use the interest rate. For a stocks and shares LISA, use a realistic long-term return assumption. Lower estimates give a more cautious projection.
5. Read the results. The calculator splits your projected pot into contributions, total bonus and growth, so you can see exactly where the money comes from.

A tip for first-time buyers

If you are saving for a property, set your horizon to the year you expect to buy and keep the growth rate conservative. That way the figure you see is closer to the deposit you can actually rely on, rather than an optimistic best case.

How the 25% bonus is calculated

The single most important rule is this: the government pays 25% of what you contribute, up to a maximum bonus of 1,000 each tax year, which is reached once you have paid in the full 4,000. The bonus is not paid on your total balance, and it is not paid on growth or interest, only on new money you add.

The bonus is paid monthly by HMRC based on the contributions your provider reports, and it then sits in your LISA earning interest or investment returns just like your own cash. Over a long horizon that compounding is what turns a series of modest top-ups into a meaningful sum.

Worked example

Imagine you pay in 200 a month, which is 2,400 over the tax year. The calculator applies the 25% bonus to that 2,400, giving a bonus of 600. So in a single year you contribute 2,400 of your own money and end up with 3,000 added to your pot, before any interest or growth.

Push that to the maximum and the picture is even better. Pay in the full 4,000 and the bonus hits its 1,000 ceiling, so 5,000 lands in your account that year. The calculator stops the bonus at 1,000 no matter how much more you try to add, because contributions above 4,000 in a single tax year do not earn any bonus at all.

Bonus by contribution level

This table shows the bonus you earn at different contribution levels in a single tax year. Use it as a quick sanity check against the calculator's output.

Notice the last row: paying in more than 4,000 still grows your pot, but the extra money earns no bonus, so most people stop at 4,000 in the LISA and use the rest of their ISA allowance elsewhere.

Projected pot over time

The real power of the calculator is showing lifetime ISA growth over many years. The example below assumes you pay in the full 4,000 every year and earn a 5% annual return, to illustrate how contributions, bonuses and growth stack up. Your own result will depend on the figures you enter.

These figures are rounded illustrations, not promises. The point they make is clear: the 25% bonus gives you a head start every year, and on a long horizon the growth on both your contributions and your bonuses does much of the heavy lifting.

The key rules the calculator follows

So the projections stay realistic, the tool is built around the actual Lifetime ISA rules:

• Annual contribution: you can pay in up to 4,000 each tax year, and this counts towards your overall 20,000 ISA allowance.
• Maximum bonus: 25% of contributions, capped at 1,000 a year.
• Opening age: you must be 18 to 39 to open a LISA, and you can keep paying in and earning the bonus until the day before you turn 50.
• First home: usable for a first property worth up to 450,000, provided the account has been open at least 12 months.
• Retirement: you can withdraw the whole pot tax-free from age 60.
• Withdrawal charge: take money out for any other reason and a 25% government charge applies, which can leave you with less than you paid in.

Why the withdrawal charge matters for your plan

Because the 25% charge applies to the whole amount withdrawn (not just the bonus), it is worth only modelling money in this calculator that you are confident you can leave untouched until a house purchase or age 60. Our full guide explains the exact maths of how this can erode your own savings.

Cash LISA vs stocks and shares LISA in the calculator

When you set the growth rate, you are effectively choosing which type of Lifetime ISA you are modelling.

• Cash Lifetime ISA: enter the interest rate your provider pays. Your balance never falls in nominal terms, which suits a first-home goal within the next few years. Keep the rate modest and realistic.
• Stocks and shares Lifetime ISA: enter a long-term return assumption. Investments can go down as well as up, so for a fair projection use a cautious figure rather than a peak market year. This version tends to suit retirement saving over a decade or more.

A simple approach: run the calculator twice, once with a low growth rate and once with a higher one, to see the range of outcomes rather than a single number.

Who this calculator suits

The Lifetime ISA calculator is most useful if you are:

• A first-time buyer wanting to see how the bonus accelerates your deposit, especially alongside our House Deposit Calculator.
• Under 40 and deciding how much to commit each month to hit a target by a certain year.
• Saving for retirement and curious how decades of bonuses and growth could compound.
• Comparing a LISA with the rest of your allowance, in which case our ISA Calculator helps you plan across the full 20,000.

Frequently asked questions

How accurate is the Lifetime ISA calculator?

It applies the real LISA rules, including the 4,000 contribution cap and the 1,000 bonus ceiling, so the contribution and bonus figures are precise. The projected pot depends on the growth rate you choose, which is an estimate, so treat the long-term total as an illustration rather than a guarantee.

Does the calculator include the 25% bonus automatically?

Yes. As soon as you enter your contributions, the tool adds the 25% government bonus (capped at 1,000 a year) and then applies your growth rate to both your money and the bonus, so you see the full effect.

Can I use it to plan a house deposit?

Absolutely. Set your time horizon to the year you hope to buy and keep the growth rate conservative for a cash LISA. For the bigger deposit picture, combine the result with our House Deposit Calculator.

Want the full background on eligibility, the withdrawal charge, LISA versus pension and whether a Lifetime ISA is worth it for you? Read our complete Lifetime ISA explained guide.

This tool is general information, not personal financial advice.

Who should use this calculator

A Lifetime ISA adds a 25% government bonus on contributions up to an annual limit, for a first home or for retirement from 60. On the maximum annual contribution that is a substantial free addition, and for eligible first-time buyers it is among the best returns available anywhere.

The catch is severe and needs stating plainly: withdrawing for anything other than a qualifying purchase or retirement incurs a 25% charge on the whole withdrawal. Because that applies to the total including the bonus, you get back less than you put in — roughly a 6.25% loss on your own money.

What this calculator assumes

• The government adds 25% on contributions up to the annual limit, paid monthly.
• The account must be opened between 18 and 39, with contributions allowed until 50.
• Funds can be used for a first home up to the property price cap, or from age 60.
• Growth is at the rate entered, tax-free within the wrapper.

Limitations — what it does not cover

• The 25% withdrawal charge outside the permitted uses, which returns less than you contributed.
• The property price cap, unchanged since launch — buying above it means the penalty applies even to a genuine first purchase.
• The 12-month rule, requiring the account to be open a year before a house purchase.
• The overall ISA allowance, which LISA contributions count towards.
• Effect on means-tested benefits, where LISA savings count as capital.
• Whether a pension is better for retirement, especially with employer matching.