Doubling-time page
How Long Does It Take to Double Money at 7%?
At a 7% annual return, money roughly doubles in about 10.2 years. The Rule of 72 gives a quick estimate of about 10.3 years, which is close enough for planning but not exact.
Exact answer
At 7% annual growth, money doubles in about 10.24 years using exact compound math.
The Rule of 72 shortcut gives 10.29 years, which is close enough for a fast estimate.
Why people use the Rule of 72 here
The shortcut divides 72 by the annual rate. At 7%, that gives 72 ÷ 7 ≈ 10.29 years. It is fast, easy to remember and surprisingly close in the mid-single-digit to low-double-digit range.
Exact vs shortcut
| Method | Result | Use case |
|---|---|---|
| Rule of 72 | About 10.29 years | Quick mental estimate |
| Exact compound math | About 10.24 years | Better for calculators and planning pages |
What changes the answer in real life
- Changing the annual return rate
- Adding recurring contributions instead of waiting for one lump sum to double
- Fees, taxes and inflation reducing the real result
- Different growth paths in real markets compared with a constant rate assumption