| Year | Start balance | Contributions | Interest | End balance |
|---|
General information tools only — not tax or financial advice. Rates and rules vary by country and change over time; confirm important figures with a qualified accountant.
How to use the compound interest calculator
Why compounding beats simple interest
With compound interest you earn interest on your interest. Growth starts slowly and accelerates, which is why starting early matters more than starting big. The table above shows the balance at each year end so you can watch the curve bend upwards.
A note on real returns
This calculator assumes a steady rate and no tax, fees, or inflation. Real accounts and investments vary year to year, so treat the result as a projection to plan with, not a promise.
Example
1,000 at 10% a year, compounded yearly, for 2 years: 1,000 × 1.12 = 1,210. Add a 100 monthly contribution and switch compounding to monthly to see how regular saving overtakes the starting amount.
Frequently asked questions
How often should interest compound?
Use the frequency on your account: most savings accounts compound daily or monthly; many investments are modelled yearly. More frequent compounding grows slightly faster.
Are contributions added at the start or end of each period?
At the end, which is the standard, slightly conservative assumption.
Does this include tax on interest?
No. Tax on savings interest depends on your country and circumstances; the figure here is the gross growth.
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