How to Find Natural Logarithms of Numbers

A natural logarithm is a logarithm to base e, the natural exponent. The natural exponent is an irrational constant, meaning its decimal value never terminates. Its approximate value is 2.718. The natural log function is the inverse of the natural exponential function. You typically use natural logarithms to solve equations containing variable exponents such as equations for determining the radioactive half-life of a chemical element. You can easily solve natural logarithms with the aid of a calculator. Solving a logarithm by hand is a difficult and time-consuming process and is rarely done for academic or demonstrative purposes.

Things You'll Need

• Calculator

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Instructions

1. • 1

     Press the natural logarithm button on your calculator. This is usually labeled with the symbol "ln" or "LN."

   • 2

     Enter the number for which you want to find the natural log.

   • 3

     Press the "=" or "Enter" button to obtain the natural log.

   • 4

     Gain a deeper understanding of the relationship between the natural log and the natural exponent by raising the natural exponent "e" to the power equal to the value of the natural log you just found. For example, ln(5) = 1.61 so e^1.61 must equal 5.