What is compound interest?

Interest calculated on both the initial principal and the accumulated interest from previous periods, producing exponential growth.

Does compounding frequency matter?

Yes, but only slightly. Daily compounding earns marginally more than monthly, and monthly beats annual. The effect grows over long horizons.

Why include monthly contributions?

Each new contribution begins compounding immediately. Over decades, regular small contributions can contribute more to the final balance than the initial principal.

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Compound Interest Calculator

See how your savings grow over time with compound interest. Add monthly contributions to watch your wealth accelerate.

Inputs

Principal Amount

Annual Interest Rate

Compounding Frequency

Duration (Years)

yrs

Monthly Contribution (optional)

Results

Final Balance

Total Contributed

Total Interest

Interest as % of Balance

Year-by-Year Growth

Year	Balance	Interest	Contributed

How to use

Enter your starting principal, expected annual return, and how often interest is compounded.
Set the duration in years and (optionally) a regular monthly contribution.
Read the final balance, total contributions, and total interest — the year-by-year table breaks it out.

FAQ

Interest calculated on both the initial principal and the interest accumulated from previous periods. Unlike simple interest, it grows exponentially.

Over long horizons, a lot. Each new contribution starts compounding immediately, so regular small deposits often end up worth more than the initial principal.

No. The calculator shows gross growth. Subtract tax on interest (or capital gains) for an after-tax projection.