Rule of 72 Calculator: How Fast Will Your Money Double?
The Rule of 72 is the simplest formula in investing: divide 72 by your annual return, and that's roughly how many years it takes your money to double.
Enter your numbers below and see your doubling timeline — plus how regular contributions speed everything up. Try our quick scenarios or customize your own.
Your Money Doubles Every
Your Return (8%)
High-Interest Savings (2.5%)
GIC (4%)
Your Doubling Timeline
What your starting amount becomes at each doubling, before new contributions.
| Doubling | Years From Now | Value |
|---|
Growth Over Time (With Your Contributions)
| Year | Portfolio Value | You Contributed | Growth |
|---|
How this calculator works:
• Years to double (Rule of 72) = 72 / annual return % — an approximation, accurate for rates between about 2% and 15%
• Exact doubling time = ln(2) / ln(1 + return) — the precise answer for a fixed annual return
• Contributions are added at the end of each month; returns are compounded monthly
• Returns are averages, not a promise: real returns vary year to year, and the rule works best over 10+ year horizons
• Results are an illustration only, not financial advice. Past performance doesn't guarantee future results
How Long Does Money Take to Double?
Rule of 72 doubling times at the return rates Canadian investors see most often.
| Annual Return | Years to Double | Typical Investment |
|---|---|---|
| 2% | 36 years | High-interest savings account |
| 3% | 24 years | Government of Canada bonds |
| 4% | 18 years | GICs |
| 5% | 14.4 years | Balanced portfolio (60/40 stocks/bonds) |
| 6% | 12 years | Conservative equity portfolio |
| 7% | 10.3 years | XEQT (lower end of historical range) |
| 8% | 9 years | XEQT (mid-range historical estimate) |
| 9% | 8 years | XEQT (higher end of historical range) |
| 10% | 7.2 years | S&P 500 long-term historical average |
| 12% | 6 years | Aggressive growth / concentrated equity |
Want the full story behind the math? Read The Rule of 72 and XEQT: How Fast Your Money Actually Doubles — including the napkin story, the inflation version of the rule, and why multiple doublings are where wealth is really built.
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