£500 a Month into a Stocks and Shares ISA for 10 Years

See what £500 a month into a Stocks and Shares ISA grows to over 10 years at a 6% return — the real final value, total invested, and tax-free growth, plus allowance used.

Written by Anurag Rath · Reviewed by the thecalcu.com team · Last updated 28 August 2026

Final ISA Value

£82,349

Open this scenario in UK ISA Calculator

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Setting aside £500 a month is a realistic target for someone with spare income after essentials, and a ten-year run is long enough for compounding to make a visible difference.

The Scenario

Initial lump sum: £0
Monthly contribution: £500
Expected annual return: 6%
Investment period: 10 years

The final value above comes from the UK ISA Calculator applying monthly compounding to each contribution, so it reflects the calculator's real formula rather than a rounded projection.

What This Means

Ten years of £500 a month is £60,000 of your own money. At a 6% annual return the pot lands a little over £82,000, so roughly £22,000 of the total is growth you never pay tax on. That tax-free treatment is the whole point of an ISA: outside one, the same gains could face Capital Gains Tax or Dividend Tax depending on how the money is held. At £6,000 a year you are using less than a third of the £20,000 allowance, so there is headroom to increase contributions later without hitting the limit.

Try Your Own Numbers

Change the monthly amount, return rate, or timeframe in the UK ISA Calculator to match your own plan. If you want to see how the same contributions would grow in a general, non-ISA account, the Compound Interest Calculator lets you model that side by side.

Frequently Asked Questions

How much of the final value is growth rather than my own money?

You put in £60,000 over the ten years, which is £500 a month for 120 months. Everything above that is investment growth, and in this scenario the growth is a bit over £22,000. In an ISA that growth is entirely free of UK tax.

Does this assume the money is invested from day one?

Each monthly contribution is invested when it is paid and compounds from that point, so earlier contributions have longer to grow than later ones. The starting lump sum here is set to zero, so the whole balance is built from the monthly payments.

What return rate does this use, and is it realistic?

It uses 6% a year, a common medium-term planning assumption for a diversified stocks and shares portfolio. Real returns are uneven and some years will be negative, so treat the final figure as a central estimate rather than a promise.

How much of my ISA allowance does £500 a month use?

£500 a month is £6,000 a year, which is 30% of the current £20,000 annual ISA allowance. You have room to contribute more if you can, and the calculator shows the allowance percentage used for whatever monthly figure you enter.

What happens if I keep going for 20 years instead of 10?

The balance grows faster than proportionally, because compounding has twice as long to work on a larger pot. Doubling the timeframe here would more than double the final value. Adjust the years in the [UK ISA Calculator](/gb/isa-calculator/) to see the exact figure.

Is a cash ISA modelled the same way?

The maths is identical, you just enter a lower, more stable return rate for a cash ISA, often 3% to 5% depending on the account. The tax-free treatment of the interest or growth is the same across ISA types.

GUIDE

UK ISA Allowance Explained: How the £20,000 Limit Works