Logarithm of a number is the power to which the base must be raised in order to obtain this number; for example, the logarithm of 25 with the base 5 is 2 since 5^2 equals 25. “ln” stands for the natural logarithm that has the Euler's constant 2.71828 as the base. This logarithm is used in many scientific calculations. Another common logarithm has the base 10 and is denoted as “log.” The following formula allows you to convert the natural logarithm to a logarithm with a different base such as 10: ln (number) = log(number)/log(2.71828).

Write down the natural logarithm you need to convert; for example ln(24).

Enter the number 24 on your calculator and press the button "ln" to calculate ln(24). In this example, ln(24) = 3.17805.

Enter the constant "e" 2.71828 on your calculator and press the button "log" to calculate log10: log10(2.71828 ) = 0.43429.

Multiply the natural logarithm by the number 0.43429 to convert the natural logarithm to log10. In this example, ln(24) converts to 3.17805 x 0.43429 = 1.3802.