Doubling-time guide
How Long Does It Take to Double Money at 7%?
A 7% return is often used in long-term investing examples, so it is natural to ask how long it takes for money to double at that rate. This is also the perfect place to understand the Rule of 72.
Fast answer
Using the Rule of 72, money doubles in about 10.3 years at 7% because 72 ÷ 7 ≈ 10.3. Using the exact compound formula gives a result closer to 10.24 years. That is close enough for planning intuition, which is why the rule is popular.
| Method | Rate | Approx. years to double | Use case |
|---|---|---|---|
| Rule of 72 | 7% | About 10.3 years | Quick mental estimate |
| Exact formula | 7% | About 10.24 years | Precise planning |
What this means in practice
If a portfolio roughly averages 7% over the long run, a balance of $10,000 could become about $20,000 in just over 10 years, $40,000 in about 20 years, and $80,000 a little after 30 years, assuming returns are steady and gains stay invested.