Rule of 72: How Long to Double Money at 8%
How many years it takes to double an investment at an 8% annual return, using the Rule of 72.
At a 8% annual return, an investment doubles in approximately 9.0 years.
Years to double
9.0 years
at 8% p.a.
Related questions
It sits in a moderate range often used for balanced portfolios or long-term PPF-adjacent planning assumptions, and it also happens to fall inside the 6-10% range where the Rule of 72 approximation is most accurate.
Related calculators
Inflation Calculator
See how inflation can erode the value of your money over time.
Compound Interest Calculator
Calculate how your money compounds over time at a given interest rate.
Simple Interest Calculator
Quickly work out interest earned or owed using the simple interest formula.
Gratuity Calculator
Calculate the gratuity amount you are eligible for based on your service.
The Rule of 72 is an approximation, most accurate for rates between 6% and 10%. For a precise doubling time at any rate, use the Compound Interest Calculator.