Calculators & Finance

Investment Growth Calculator

Projected growth with contributions, fees and inflation.

What it does. Compounding is the reason long-horizon investing works, and fees compound against you in exactly the same way. A 1% annual fee sounds trivial and removes roughly a fifth to a quarter of the final pot over forty years, because it is charged on the whole balance every year including the growth it already prevented.

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How to use Investment Growth Calculator

Enter the starting amount, monthly contribution and horizon.
Set an expected return, the annual fee and inflation.
Compare the nominal figure with the real, after-fee one.

What a 1% fee actually costs

£500 a month for 40 years at 7% grows to roughly £1.2 million before fees. At 6% — the same return minus a 1% fee — it grows to about £930,000.

That single percentage point costs around a quarter of the outcome. It is not charged on the growth; it is charged on the balance, every year, forever.

This is the single highest-leverage number in personal investing, and it is also the one entirely within your control. Expected returns are not controllable. The fee is on the factsheet.

Nominal against real

A projection of £1.2 million in forty years is not £1.2 million of today’s money. At 2.5% inflation it buys roughly what £450,000 buys now.

That is not a reason to despair — wages and contributions usually rise with inflation too — but a nominal figure alone is misleading about what the money will do.

The useful habit is to look at the real column and ignore the nominal one entirely. It is the only figure that answers the question you were actually asking.

The assumptions matter more than the arithmetic

Expected return is an assumption, not a fact. Long-run global equity averages sit near 7% nominal, and no decade is average.
Sequence of returns matters near the end. A crash at 60 hurts far more than the same crash at 30.
Contributions rarely stay flat. Most people can raise them over a career.
Tax wrappers change the answer substantially, and vary by country.
Nothing here is advice. It is arithmetic with assumptions you supply.

Treat any single projection as one scenario. Running it at 5%, 7% and 9% is more informative than any one number, because the spread is the honest answer.

Frequently asked questions

How much difference does a 1% fee make?

Roughly a quarter of the final pot over forty years. It is charged on the whole balance every year, including on growth it already prevented — which is why it compounds against you the same way returns compound for you.

What return should I assume?

Long-run global equity averages sit near 7% nominal, but no individual decade is average. Run the projection at 5%, 7% and 9% — the spread is a more honest answer than any single figure.

Why is the real figure so much lower?

Inflation. At 2.5%, money loses roughly half its purchasing power over 28 years. The real column is the one that answers what the money will actually buy.

Does the order of returns matter?

Yes, and increasingly as you approach the end. The same average return with a crash early is far kinder than the same crash near retirement, when the balance is largest.

Is this financial advice?

No. It is arithmetic applied to assumptions you supply. Expected returns, fees and inflation are inputs, not predictions, and nothing here accounts for your circumstances or tax position.