Investment Growth Calculator
Enter a starting amount, a regular contribution and an assumed return, and see what the balance could look like after fees and inflation have taken their cut.
Formula and method
The balance is built up step by step, growing by (1 + annual return) 1/steps − 1 at each one.
The annual fee comes off the same way, at 1 − (1 − fee) 1/steps per step, so it compounds against you just as much as the return compounds for you.
Contributions land at the start or end of each period, whichever you pick. The inflation-adjusted figure divides the balance by (1 + inflation) for every year that passes.
The "growth" column is the balance change with contributions and fees stripped out, so the numbers add up.
Worked example
€10,000 invested at 10% a year, no contributions, compounded annually:
Year 1: €11,000. Year 2: €11,000 × 1.10 = €12,100, of which €2,100 is growth.
Add a 1% annual fee and the balance falls behind a little more each year. Over decades that small annual bite adds up to real money.
FAQ
Frequently asked questions
How does the calculator work out compound growth?
It grows the balance step by step at the equivalent periodic rate, adds contributions on their own schedule, and takes the annual fee out pro rata at each step.
What annual return should I use?
There is no right number. Nobody can tell you what markets will do next, so it is more useful to run a few assumptions side by side than to trust one.
What does the inflation-adjusted figure actually show?
It divides the projected balance by (1 + inflation) for each year, so you see roughly what that money would buy today rather than a bigger nominal number that buys less.
Does it matter if I contribute at the start or end of the month?
A little. Contributing at the start gives each payment one extra period to grow, so the projected balance ends up slightly higher than paying at the end.
Is tax taken off?
No. This is a pre-tax projection. Income, dividend, withholding and capital gains tax are all left out, along with any charges you haven't entered as the fee.
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