Returns the logarithm of a number to the base you specify.

Syntax

Log(number, [base])

The Log function syntax has the following arguments:

Number Required. The positive real number for which you want the logarithm.

Base Optional. The base of the logarithm. If base is omitted, it is assumed to be 10.

Examples

Formula

Description

Result

=Log(10)

Logarithm of 10. Because the second argument (base) is omitted, it is assumed to be 10. The result, 1, is the power to which the base must be raised to equal 10.

1

=Log(8,2)

Logarithm of 8 with base 2. The result, 3, is the power to which the base must be raised to equal 8.

3

=Log(100,10)

Logarithm of 100 with base 10. The result, 2, is the power to which the base must be raised to equal 100.

2

=Log(100,2)

Logarithm of 100 with base 2. The result, 6.643, is the power to which the base must be raised to equal 100.

6.64385618977472

=Log(86, 2.7182818)

Logarithm of 86 with base e (approximately 2.718). The result, 4.454, is the power to which the base must be raised to equal 86.

4.45434734288829