About this calculator
The Rule of 72 is the fastest way to grasp the power of compounding: divide 72 by your rate of return to estimate the years it takes to double your money. This calculator does it instantly and shows how small changes in return dramatically change the timeline.
What it shows you
- Years to double your money at a given return
- The return needed to double by a target year
- How rate differences compound over decades
- Doubling timelines side by side
- The long-run cost of a slightly lower return
Why it matters
Nothing teaches the value of rate of return — or starting early — faster than the Rule of 72. It is a simple, memorable hook that makes a client feel the math instead of just hearing it.