Rule of 72 Calculator
Free Rule of 72 calculator. Find out how many years it takes to double your money at any interest rate. Simple, instant calculation with examples.
Rule of 72 — Doubling Time
Formula: Years to Double = 72 ÷ Annual Return Rate
| Annual Return | Years to Double | Example Investment |
|---|---|---|
| 2% | 36 years | Savings account |
| 4% | 18 years | Bonds, CDs |
| 6% | 12 years | Balanced fund |
| 7% | 10.3 years | S&P 500 (inflation-adjusted) |
| 10% | 7.2 years | S&P 500 (nominal) |
| 12% | 6 years | Growth stocks |
| 15% | 4.8 years | Aggressive growth |
Power of Multiple Doublings
| Doublings | $10K becomes | $50K becomes | At 10% return |
|---|---|---|---|
| 1x | $20,000 | $100,000 | ~7 years |
| 2x | $40,000 | $200,000 | ~14 years |
| 3x | $80,000 | $400,000 | ~22 years |
| 4x | $160,000 | $800,000 | ~29 years |
| 5x | $320,000 | $1,600,000 | ~36 years |