Simple Formula for Converting Compound Interest Rates

 This workbook has a simple formula to convert compound interest rates.



g = Current interest rate

f = Number of times the current rate compounds per year

t = Number of times the converted new rate compounds per year

This lookup table grabs two of the numbers for the formula

Continuous compounding in Excel is generally calculated as:

The natural log of the annual rate


Solving for the annual rate given the continuous rate

e raised to the power of the continuous rate



e =2.71828182845904…

There is also a  is a simpler version of the formula that can be copy/pasted into another worksheet without a lookup table:

Download workbook “Convert_Compound

Don Pistulka
Don Pistulka

Retired Credit Union CFO - Finance
Background: over 40 years in investments, asset/Liability management, banking, securities trader.
Worked for: California Credit Union, WesCorp, CalFed S&L, Crocker Bank, Carroll McEntee, Federal Home Loan Bank Board (D.C.), Western Asset Management, Security Pacific National Bank.


    1. Spence,
      It depends. Over what period of time? A $10,000 simple interest investment at 15% for two years, would earn $1,500 per year or $3,000. The same investment compounded annually, would earn $3,225. If you are asking for an equvilent interest rate, again it depends on the term. For the example above, the interest rate for a $10,000 investment worth $13,000 in two years would be equivalent to a 14.0175% compound annual interest rate. Do you have a specific type of loan or investment in mind? Can you give me an example?

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