Tiny Toolkit

Compound Interest Calculator

Calculate how an investment grows over time with compound interest and regular monthly contributions. Choose from annual, quarterly, monthly, or daily compounding to see how frequency affects returns. A year-by-year chart visualises the gap between what you invested and what compound growth adds on top.

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Frequently Asked Questions

What is the difference between simple and compound interest?
Simple interest is calculated only on the original principal. Compound interest is calculated on the principal plus any interest already earned, so your earnings grow exponentially over time.
Does compounding frequency matter?
Yes, but the effect is smaller than most people expect. Daily compounding earns slightly more than monthly or annual compounding at the same rate — the difference is most visible over long time horizons.
How are monthly contributions factored in?
Each monthly contribution is added to the balance before the next compounding period, so contributions benefit from compound growth for the remaining term. Earlier contributions grow the most.

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