Rule of 72 Calculator

Estimate how long it takes to double your money.

Years to double (years) 9

Formula: years ≈ 72 ÷ rate

Step-by-step with your numbers:

1. Values used:

2. Annual rate = 8 %

4. Years to double = 9years

Did we solve your problem today?

A quick mental shortcut for doubling time.

The math behind it

years to double ≈ 72 ÷ annual percentage rate.

At 8% → 72 ÷ 8 = 9 years to double.

How accurate?

Very close for rates between about 6% and 10%.