candlestick_chartChartsQuest
tools.kicker·tools.cat.investment

Rule of 72 Calculator

Mental math for compounding — close enough to use, fast enough to remember.

infotools.disclaimer

tools.results

Years to double9.0

Heuristic — best between 5–10%, slightly off at extremes.

tools.whatItDoes

Divide 72 by the annual return to estimate the years required to double an investment under compounding. The calculator returns years to double for the input return.

tools.howToUse

  1. Enter the expected annual return percentage.
  2. Read the estimated years to double.

tools.formula

Years to Double ≈ 72 ÷ Annual Return %

tools.example

8% annual return → 72 ÷ 8 = 9 years to double. 6% annual return → 12 years.

tools.commonMistakes

  • Treating the shortcut as exact. The Rule of 72 is a heuristic, not a formula.
  • Using unrealistic return assumptions.
  • Ignoring inflation. Real doubling time is longer.
sports_esports

tools.simulatorCtaTitle

tools.simulatorCtaBody

Simulator →
account_circle

tools.signupCta

Create a free ChartsQuest account to read the full article — and unlock the entire five-level quest while you're here.

Sign up free

tools.relatedTools

trending_up

Compound Interest Calculator

Project how a starting balance grows with compounding and recurring contributions.

tools.useTool →

savings

Investment Growth Calculator

Project investment value with contributions, returns, and an optional inflation adjustment.

tools.useTool →

percent

ROI Calculator

Compute return on investment — net profit, ROI percentage, and annualized ROI.

tools.useTool →

tools.exploreMore →

tools.faqHeading

How accurate is the Rule of 72?add

Very accurate between 5% and 10% annual returns. Diverges slowly at extremes; for higher returns the Rule of 70 or 69 is closer.

Does this account for inflation?add

No. Subtract inflation from the return to get a real-return doubling estimate.

What return should I use?add

There's no right answer — test multiple scenarios rather than fixing on one optimistic number.

Do I need an account?add

No, the tool is free and works without signing in.

tools.disclaimer