Compound interest calculator
See what regular saving grows into over time.
- Runs in your browser — nothing you enter is uploaded
- No sign-up, no quotas, free to use as often as you like
How it works
Compound growth is famously hard to estimate intuitively — people consistently guess low, because the growth accelerates. Seeing the final balance next to the amount actually contributed is usually more persuasive than any percentage.
What the numbers mean
The final balance is what you end up with. The amount you put in is your starting sum plus every monthly contribution. The difference between them is growth — and on long horizons it commonly exceeds everything you contributed.
Monthly compounding is assumed
Interest is added every month and then earns interest itself. Accounts that compound annually will grow slightly more slowly than shown; the difference is small but real.
What is deliberately ignored
Tax, platform fees, fund charges and inflation are all excluded. Each one reduces the real outcome, and inflation in particular means the final figure buys less than the same figure would today. Treat the result as a comparison between scenarios rather than a prediction.
Returns are not guaranteed
A fixed yearly return is an assumption, not a fact. Investment returns vary and can be negative. This is arithmetic, not financial advice.
Compound interest calculator — questions
Does this account for inflation?
No. The final figure is in today's currency units and will buy less in future than it would now.
Does it include fees or tax?
No. Both reduce real outcomes, so treat the result as an upper bound.
How often is interest compounded?
Monthly. Annual compounding grows slightly more slowly.
Is this financial advice?
No. It is arithmetic on the assumptions you enter.