METRONMETHOD. REASON. LEARN.
Everyday Lab

Compare simple and compound interest

Imagine leaving a starting amount untouched. Compare adding interest only on the original amount with adding interest on the growing balance.

Your experiment

Change any value to update the result. Use the stated units.

What the numbers tell us

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Why it works

simple = P(1 + rt); compound = P(1 + r)ᵗ

Assumptions and limits

A mathematical model with a constant rate, annual compounding, no deposits, withdrawals, fees or tax. The rate is illustrative, not an available financial product or personal advice.

Try a small challenge

Simple interest on $100 at 5% per year for 2 years: final balance?
A little hint

Interest is $5 each year.

Understand the idea: Percentages →