Rule of 72 as of · 161
In a household notebook, Rule of 72 is judged from . The line is ““I will start when markets are calm”” and the figure in the sum is 72. A blinking gain on a screen is not the reason. Before optimising 0.2% of expected return, ask whether the contribution rate can move by 2–5 points.
A mental model for doubling time: divide 72 by the rate — useful, approximate, and easy to abuse. The Rule of 72 estimates years to double money at a constant compound rate — a pocket approximation, not a prospectus. Rule of 72 sits in the foundations family of this atlas: mechanisms first, products second, hype never.
Use the calculator for scenarios, then return to the section pages when you want the vocabulary behind the curve. No. Tool-Lifes pages are educational atlases. Decisions need your goals, constraints and, when appropriate, a licensed adviser. Do I need a high return for compounding to matter?
Higher net rates help, but time and contributions often dominate — especially early. Costs and behaviour can erase a “good” rate. Treat outputs as scenario sketches. Vary contribution, rate, fees and inflation to see which lever moves your goal date. Always ask whether a figure is nominal or real. A high nominal path can still lose purchasing power.
For Rule of 72 in , the figure that stays is 72, named ““I will start when markets are calm”.” Sparkle is not a figure.72
Figures to keep
- Year of the rule
- 72
- Figure in the sum
- 72
- Item
- Rule of 72
- Reason kept
- “I will start when markets are calm”