Compound growth calculator
I built this as a reminder to start investing early. Not to start big, but to start early. The dollars you put in first are the ones that compound longest, so when you start matters more. So, start before you feel you are ready...
The other half is automation. Deciding to invest is easy; doing it every two weeks for forty years is not. So take the deciding out of it. Move the money to an investment account on payday, have it invest it for you, and you never touch the dial. Set it up once and leave it alone. Only look at it every year or so. Your future self will thank you for it.
Contributions are added at the end of each period, not the start.
Show returns in:
Assumptions
- Contributions land at the end of each period (ordinary annuity), not the start.
- A stated annual rate is converted to a sub-annual period rate using the true effective equivalent, (1+r)^(1/m)−1, so a monthly contribution stream against "7%" compounds to exactly 7.000% a year, not slightly more.
- Tax, when entered, is applied once at the end, to total gain only — growth compounds untaxed throughout the holding period. This models a buy-and-hold account, not one with annually distributed income.
- The real-dollar view deflates by the exact Fisher relation, not the rough r−i shortcut, which understates the drift the shortcut introduces over long horizons.
- Contribution indexing, when switched on, escalates at 2% a year (the Bank of Canada's inflation-control target), independent of whatever inflation rate is entered above.
- Every contribution counts, including the first. N years of contributions always produce exactly N payments.
Amount invested
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Simple earnings
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Compound earnings
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Show the year-by-year numbers Hide the year-by-year numbers
| Year | Amount invested | Earnings | Total |
|---|
Same contribution, same rate, same end date — the only thing that changes is when you start.
Start at age 23
Start at age 33
What those 10 years cost