This Rule of 72 calculator computes the approximate period to double one's investment.

INSTRUCTIONS: Enter the following:

• (r) This is the annual interest rate

Doubling Period (R72): The calculator estimates the number of periods to double one's investment. 

The Math / Science

This formula approximates the period to double one's investment based on the earning percentage (r) per period.  The result is the number of periods in the same units (e.g. years for 5% per year) as the period unit for the rate of return.  This serves as a quick comparison for evaluating investments.

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• Rule of 72: Provides a quick estimate on time to double an investment
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• Current Mortgage Rates:
  • 30 Year Fixed Interest Rate: 6.76 %
  • 15 Year Fixed Interest Rate: 6.15 %
  •  7/6 SOFR ARM: [Invalid Constant]

External Links

• Business Insider  11 Personal Finance Equations You Need To Know