Rule of 72 Calculator
Summary
Uses the Rule of 72 — a mental math shortcut — to estimate how many years it takes for an investment to double at a fixed annual rate.
Example
At 6% interest, your money doubles in 72 ÷ 6 = 12 years. At 9%, it doubles in just 8 years.
Explanation of Results
The Rule of 72 works by dividing 72 by the annual interest rate. It's a quick approximation — the actual doubling time from exact compound interest is very close but slightly different. It's most useful for comparing rates at a glance without a calculator.
