Unlocking the Rule of 72 [Finance]: A Simple Guide to Doubling Your Investment

Definition & Meaning

The Rule of 72 is a financial formula that helps investors estimate the number of years required to double their investment at a fixed annual interest rate. To use this rule, divide the number 72 by the expected annual interest rate. For instance, if you invest $100 at a 6 percent interest rate, it will take approximately 12 years for your investment to double (72 divided by 6 equals 12). This rule is most accurate for lower rates of return and serves as a quick mental calculation for investors.

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Real-world examples

Here are a couple of examples of abatement:

Example 1: If a person invests $1,000 at an 8 percent interest rate, using the Rule of 72, it would take about 9 years to double their investment (72 divided by 8 equals 9).

Example 2: A hypothetical example would be a $5,000 investment at a 4 percent interest rate, which would take approximately 18 years to double (72 divided by 4 equals 18).

State-by-state differences

This is not a complete list. State laws vary and users should consult local rules for specific guidance.

State Notes
California No significant variations in the application of the Rule of 72.
New York Commonly used in financial planning but no specific legal statutes apply.
Texas Used in investment discussions; no legal variations.

Comparison with related terms

Term Definition Difference
Rule of 70 A similar formula to estimate doubling time using 70 instead of 72. Provides a slightly quicker estimate, often used for higher interest rates.
Compound interest Interest calculated on the initial principal and also on the accumulated interest. The Rule of 72 is a tool to estimate outcomes of compound interest.

What to do if this term applies to you

If you're considering an investment and want to know how long it will take to double your money, use the Rule of 72 as a quick reference. For more complex financial decisions, consider consulting with a financial advisor or utilizing US Legal Forms' templates for investment agreements and financial planning documents.

Quick facts

Attribute Details
Typical use Investment planning
Accuracy Most accurate for interest rates between 6% and 10%
Calculation 72 divided by the interest rate

Key takeaways

Frequently asked questions

It is a formula to estimate the number of years needed to double an investment based on a fixed annual interest rate.