How Long to Double Money at 6%
At 6% a year, money doubles in 11.9 years. The Rule of 72 says 12.0.
Doubles in
11.9 years
Quadruples in
23.8 years
Grows 8 times in
35.7 years
Rule of 72 estimate
12.0 years
What different amounts become
| Start | After 11.9 years | After 23.8 years | After 35.7 years |
|---|---|---|---|
| $1,000 | $2,000 | $4,000 | $8,000 |
| $5,000 | $10,000 | $20,000 | $40,000 |
| $10,000 | $20,000 | $40,000 | $80,000 |
| $25,000 | $50,000 | $100,000 | $200,000 |
| $50,000 | $100,000 | $200,000 | $400,000 |
| $100,000 | $200,000 | $400,000 | $800,000 |
Growth over time at 6%
| Years | $1,000 becomes | $10,000 becomes | Growth |
|---|---|---|---|
| 5 | $1,338 | $13,382 | 1.34x |
| 10 | $1,791 | $17,908 | 1.79x |
| 15 | $2,397 | $23,966 | 2.40x |
| 20 | $3,207 | $32,071 | 3.21x |
| 25 | $4,292 | $42,919 | 4.29x |
| 30 | $5,743 | $57,435 | 5.74x |
| 40 | $10,286 | $102,857 | 10.29x |
| 50 | $18,420 | $184,202 | 18.42x |
How it is worked out
Years to double = ln(2) / ln(1 + r)
ln = natural logarithm, r = rate as a decimal.
The Rule of 72 is the shortcut version. Divide 72 by the rate.
At 6% the shortcut is off by 0.1 years.