The log or logarithm of a number is the power (or exponent) to which a specific base must be raised to obtain that number. Logs answer the question, ‘To what power should the base be raised to get a given number?’
The general formula for a logarithm is:
Logb(x) = y
This means that ‘b’ (the base) raised to the power of ‘y’ equals ‘x’:
by = x
Log Base 2
One of the common types of logarithms is Log Base 2 which uses 2 as the base. This logarithm is often used in computing and binary systems.
For example, log base 2 of 8 is 3 because 23=8. Below is the formula:
Log2(8) = 3
I will show you ways to calculate Log Base 2 in Excel.
Method #1: Using the LOG Function
Using the LOG function, you can calculate Log Base 2 in Excel, specifying the base argument as 2. The LOG function returns a number’s logarithm to the base you provide.
The syntax of the LOG function:
=LOG(number, [base])
The ‘number’ argument is required and represents the positive real number for which you want the logarithm.
The ‘base’ argument is optional and is the base of the logarithm. If you omit it, the function defaults to base 10.
Suppose you have a list of numbers in column A and want to calculate their Log Base 2 in column B.
You can use the below formula to do it:
=LOG(A2,2)
Also read: How to Calculate Antilog in Excel (Formula)
Method #2: Using the LOG10 Function
You can calculate the Log Base 2 of a number using a LOG10 formula dividing the base-10 logarithm of the number with the base-10 logarithm of base 2.
The LOG10 function calculates the base -10 logarithm of a number.
Syntax of LOG10 function:
LOG10(number)
Note: You can use the LOG function without providing a base. If no base is specified, the function defaults to base 10.
Suppose you have a list of numbers in column A and want to calculate their Log Base 2 in column B.
You can use either of the below formulas to do it:
=LOG10(A2)/LOG10(2)
=LOG(A2)/LOG(2)
The formula calculates the logarithm of a number to base 2 by first computing the base-10 logarithm of the number and then adjusting it using the logarithm of 2.
Note: Use this method if you have a pre-2010 version of Excel that does not support the LOG function with a base argument. Otherwise, use Method #1 which is simpler and more intuitive because it directly specifies that you want a logarithm with base 2.
Here’s a more conversational rewrite:
So, there you have it! That’s how you can calculate log base 2 in Excel. Pretty neat, right? I hope this little walkthrough made things clearer for you.
If you’re still scratching your head or have any questions, don’t hesitate to ask.
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