Rule of 72 calculator
See how long it takes to double your money at a given interest rate — or the rate needed to double it in a set time. Compare the Rule of 72, 70 and 69.3. Nothing is uploaded.
What to find
Years to double ≈ 72 ÷ rate. Best for rates around 6–10%.
Annual rate (%)
Years to double
—Years to double (Rule of 72)
—Rule of 70
—Rule of 69.3
Everything runs in your browser. No upload, no sign-up.
How it works
STEP 1
Pick what to find
Years to double from a rate, or the rate needed for a chosen time.
STEP 2
Enter one number
Type the annual interest rate, or the number of years to double.
STEP 3
Read the answer
The Rule of 72 result appears instantly, with the 70 and 69.3 variants. All private.