How this Rule of 72 calculator works
The Rule of 72 is a quick mental shortcut for estimating how long it takes money to double.
Years to Double ≈ 72 ÷ Annual Return
When it is useful
- Comparing investment return assumptions quickly.
- Explaining compound growth in simple terms.
- Estimating inflation’s impact on purchasing power.
Important note
The Rule of 72 is an approximation. The exact result uses logarithms and can differ slightly at very low or very high rates.
How to use this calculator
- Enter realistic values that match your current situation.
- Press Calculate to refresh the estimate.
- Compare the main result with the supporting details in the result panel.
- Change one input at a time to see which variable affects the result most.
Planning note: Rule of 72 Calculator gives an educational estimate. It does not include every tax rule, fee, platform policy, market condition, or personal constraint, so use it as a quick planning reference rather than a final decision.