How Long to Double Money at 11%
At 11% a year, money doubles in 6.6 years. The Rule of 72 says 6.5.
Doubles in
6.6 years
Quadruples in
13.3 years
Grows 8 times in
19.9 years
Rule of 72 estimate
6.5 years
What different amounts become
| Start | After 6.6 years | After 13.3 years | After 19.9 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 11%
| Years | $1,000 becomes | $10,000 becomes | Growth |
|---|---|---|---|
| 5 | $1,685 | $16,851 | 1.69x |
| 10 | $2,839 | $28,394 | 2.84x |
| 15 | $4,785 | $47,846 | 4.78x |
| 20 | $8,062 | $80,623 | 8.06x |
| 25 | $13,585 | $135,855 | 13.59x |
| 30 | $22,892 | $228,923 | 22.89x |
| 40 | $65,001 | $650,009 | 65.00x |
| 50 | $184,565 | $1,845,648 | 184.56x |
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 11% the shortcut is off by 0.1 years.