Compound Growth Calculator

Explore how regular contributions grow under an assumed rate of return, and what delaying the start costs. The concepts are explained in How Money Grows: Compound Interest Explained.

Assumptions (defaults are illustrations, not forecasts — edit freely)

Starting amount ($)

Monthly contribution ($)

Assumed annual return (%) default 7% — hypothetical; markets vary and have negative years

Years invested

Compare a delayed start (years) 0 = no comparison

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Hypothetical ending balance

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Total contributed

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Hypothetical growth

Hypothetical illustration — actual returns vary and may be negative. Default assumptions are labeled and editable; they are illustrations, not forecasts.

This calculator requires JavaScript. The compound interest lesson covers the same concepts with worked examples that need no calculator.