How Long to Double Money at 5%
At 5% a year, money doubles in 14.2 years. The Rule of 72 says 14.4.
Doubles in
14.2 years
Quadruples in
28.4 years
Grows 8 times in
42.6 years
Rule of 72 estimate
14.4 years
What different amounts become
| Start | After 14.2 years | After 28.4 years | After 42.6 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 5%
| Years | $1,000 becomes | $10,000 becomes | Growth |
|---|---|---|---|
| 5 | $1,276 | $12,763 | 1.28x |
| 10 | $1,629 | $16,289 | 1.63x |
| 15 | $2,079 | $20,789 | 2.08x |
| 20 | $2,653 | $26,533 | 2.65x |
| 25 | $3,386 | $33,864 | 3.39x |
| 30 | $4,322 | $43,219 | 4.32x |
| 40 | $7,040 | $70,400 | 7.04x |
| 50 | $11,467 | $114,674 | 11.47x |
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 5% the shortcut is off by 0.2 years.