Guide
How Long Does It Take to Double Your Money?
Doubling time depends on your rate, fees, and compounding. Here’s a simple Rule of 72 estimate, a quick table, and how to get a more precise answer in the calculator.
Published: March 12, 2025 · Updated: December 21, 2025 · By FinToolSuite Editorial
Disclaimer
Educational purposes only; not financial advice. Examples are illustrative; real returns vary and investments can go down as well as up. Fees, taxes, inflation, and rules vary by provider and country.
Try the calculator
Set your rate, compounding, and horizon to see when your balance reaches roughly double.
Open the calculatorQuick answer
Rule of 72: years to double ≈ 72 ÷ interest rate (%). It’s a rough estimate; the calculator gives a more precise answer. Learn more: Rule of 72 explained.
The Rule of 72
The Rule of 72 is a shortcut to estimate doubling time for moderate rates. Divide 72 by the annual rate (in percent) to get an approximate number of years to double.
Rate → estimated doubling time
| Rate (approx.) | Estimated years to double |
|---|---|
| 2% | ~36 years |
| 3% | ~24 years |
| 5% | ~14–15 years |
| 7% | ~10–11 years |
| 10% | ~7–8 years |
Illustrative only; real outcomes vary.
How to get a precise answer in the calculator
- Enter a starting amount (e.g., £1,000) and set contributions to £0.
- Enter your rate assumption and choose compounding frequency.
- Increase the time horizon until the ending value is around double (~£2,000 in this example).
- Use the chart to spot where the line crosses the doubling point.
Worked example
£1,000 at 5%, monthly compounding, £0 contributions. Rule of 72 estimate: ~14–15 years. Calculator (illustrative): around 14 years to reach ~£2,000.
What can slow down doubling
- Fees
- Taxes
- Inflation (purchasing power)
- Variable returns (if investments)
FAQ
How long to double money at 5%?
Rule of 72 gives ~14–15 years. A calculator with monthly compounding shows roughly the same range.
Does compounding frequency change doubling time?
Yes, slightly. More frequent compounding can shorten the time a bit.
Is the Rule of 72 accurate?
It’s an estimate that works best for moderate rates. The calculator is more precise.
What about fees and taxes?
They reduce net returns and can extend the time to double.
Can I double money with monthly contributions?
Contributions add new money; doubling the original principal is different from doubling total deposits. Model both in the calculator.
Does inflation matter for “doubling”?
Doubling in nominal terms may not double purchasing power if inflation is high.
Is doubling guaranteed?
No. Returns vary, and investments can lose value.
How do I find the exact time in a calculator?
Adjust the years until the ending balance is about twice the starting amount for the rate and compounding you chose.
Compare scenarios in the tool
Run conservative, base, and optimistic rates to see how doubling time changes.
Open the calculator