Your assumptions
Final balance
Total contributions
Total interest
Effective annual rate
Growth over time
Contributions vs. interest per year
Year-by-year breakdown
| Year | Paid in this year | Interest this year | Total paid in | Balance |
|---|
Time to goal
Uses the starting amount, monthly contribution and return above.
Required monthly savings
Uses the starting amount and return above.
How compound interest works
Compound interest means you earn a return not only on the money you put in, but also on the return you have already earned. In the first years most of the growth comes from your own contributions; over time the interest itself starts doing most of the work, which is why the balance curve bends upwards.
This calculator compounds monthly: each month your contribution is added and the balance then grows by one twelfth of the annual return. The effective annual rate shows what that monthly compounding adds up to over a year – for example, 7% compounded monthly is (1 + 0.07 / 12)12 − 1 ≈ 7.23% per year.
What you can calculate
- Overview – your final balance, how much you paid in, how much came from interest, and a year-by-year breakdown.
- Goal planning – how many years it takes to reach a target amount with your current savings.
- Required savings – how much you need to save each month to reach a target within a set time.
Frequently asked questions
Does the calculator include taxes, fees or inflation?
No. All results are before tax, fees and inflation, and assume the same return every year. Real investments go up and down, so treat the numbers as an estimate.
Does changing the currency convert my amounts?
No. The currency only changes how amounts are shown. Enter your figures in the currency you choose.
Are my numbers saved or sent anywhere?
No. All calculations run in your browser. Only your chosen currency and theme are remembered on your own device.
What is my tipping point?
Your tipping point is the first year in which the interest you earn is larger than what you pay in that year – from then on, your money does more of the work than you do. The note above the “Contributions vs. interest per year” chart shows your tipping point, and the chart shows how the two compare year by year.