Investment growth calculator
See how a lump sum and regular contributions could grow over time inside an ISA, a Lifetime ISA, a pension or a general investment account. The calculator builds in the 25% Lifetime ISA bonus and pension tax relief automatically, so you can compare wrappers on a fair basis rather than a headline contribution.
Investment growth calculator
Add your investments, set your assumptions, and see how your money could grow over time — including tax relief on pensions and the Lifetime ISA bonus.
Your investments
Growth and withdrawals are tax-free. You can pay in up to £20,000 across your ISAs each tax year.
Contributions attract tax relief and growth is tax-free, but you can't usually access the money before age 55 (57 from 2028).
Your assumptions
Your projection
Breakdown by investment
| Investment | Today | Paid in | Relief / bonus | Projected |
|---|---|---|---|---|
| Stocks & Shares ISA | £20,000 | £60,000 | — | £154,517 |
| Workplace pension | £45,000 | £72,000 | £18,000 | £271,575 |
This calculator is for illustration only and is not financial advice. Projections assume a constant growth rate, which real investments never deliver — values will rise and fall along the way. The value of investments can go down as well as up, and you may get back less than you put in. Tax treatment depends on your individual circumstances and may change.
Who this calculator is for
First-time savers deciding between an ISA and a Lifetime ISA, pension savers wanting to visualise the effect of tax relief, and anyone wanting a clear picture of what steady monthly investing can do over 10, 20 or 30 years.
The 2026/27 rules it uses
- Stocks & Shares ISA: £20,000 annual subscription limit, all growth free of UK income and capital gains tax.
- Lifetime ISA: £4,000 annual limit, 25% government bonus (up to £1,000 per year), available until age 50.
- Pension: contributions grossed up at your marginal rate (basic 20%, higher 40%, additional 45%).
- Growth is compounded on the projection frequency you choose and shown before inflation.
Frequently asked questions
Is the projected return guaranteed?
No. The assumed growth rate is illustrative only — real investment returns vary year to year and can be negative. Use this as a planning aid, not a promise.
Does it account for inflation?
The main figures are in today's money terms before inflation. If you want a real-terms view, use a growth assumption net of your inflation expectation (for example 5% instead of 7%).
For guidance only, not financial advice. Investments can fall as well as rise and you may get back less than you invest.