Finance

Interest Calculator

Calculate how money grows under either simple interest or compound interest assumptions.

Preparing Interest Calculator

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Input

Choose simple or compound interest, then enter the starting amount, rate, and time horizon to estimate growth. This tool shows the result instantly without step-by-step output.

Input summary

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How to use Interest Calculator

Pick the interest model that matches the account or worksheet, and the calculator will show how the balance grows under that rule.

What this calculator is for

This calculator is for classroom finance work, savings planning, and quick comparisons between linear growth and compounding growth. It is especially useful when the wording of a problem changes the entire interest method.

Tips

Use simple interest only when the problem or contract says interest is not added back into the earning base each cycle.
For compound mode, make sure the compounding frequency matches the product terms because annual and monthly compounding produce different outcomes.