**LN Function in Excel (Table of Contents)**

## LN in Excel

A logarithm is not a walk in the park to understand and digest especially if you are a non-mathematical student.

In simple terms logarithm means, “How many of one number do we multiply to get another number?”

**Example:** How many 5^{s} we need to multiply to get 125?

**Answer: **5 * 5 * 5 = 125. We need to multiply the number 5 three times to get the number 125. Therefore, the logarithm is 3.

In a mathematical way, we can write it as the below one.

**Log _{5} (125) =3**

The logarithm of 125 with a base number of 5 is 3.

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**A relationship between Logarithms & Exponents**

Here exponent says how many times you need to multiply the base value.

Now, the logarithm equation becomes as the below.

**5**^{?}** =625**

Therefore logarithm answers the question “What exponent do we need for one number to become another”.

It is a built-in function in excel that returns the natural logarithm of a given number.

**Natural Logarithm: **Base “e”

e is a Euler’s Number that is equal to 2.718282. This is called a “natural logarithm”.

### LN Formula in Excel

Below is the LN Formula in Excel :

### Explanation of LN Function in Excel

The LN function in excel has one argument i.e. number.

**Number:**The number that you give to get the natural logarithm number.

The natural logarithm of a number is the opposite of EXPONENTIAL function. Below example illustrates the same.

Therefore, the exponential number of number 1 is 2.718282 and natural logarithm number of 2.718282 is 1.

**How to use LN Function in Excel?**

LN function in Excel is very simple and easy to use. Let understand the working of LN function in Excel by some LN Formula example.

There is no day-to-day example to explain the LN function in Excel with live examples. In this article, I will brief you about how this works and error types one by one.

### Example #1

You cannot supply any negative number to LN function. If you supply the negative number to this function, it will throw the error as **#NUM. **Any number that is equal to or less than zero LN function cannot return the value against it.

By applying the formula in cell C2.

So the Result will be:

Similarly, it is applied to other cells in that column to get the desired output.

### Example #2

You cannot supply number zero too to LN function. If you supply the number zero to this function, it will throw the error, as **#NUM. **Similar to the negative number LN function requires the number to be greater than zero, otherwise, we will get number error.

** **

By applying the formula in cell C2.

So the Result will be:

Similarly, it is applied to other cells in that column to get the desired output.

### Example #3

You cannot supply anything other than a rational number to LN function. If given so it will give the error as **#VALUE!** We cannot supply any operators, symbols etc… Anything other than a positive number, it will give the error as #VALUE!

By applying the formula in cell C2.

So the Result will be:

Similarly, it is applied to other cells in that column to get the desired output.

### Example #4

The value we need to give to LN function starts with anything greater than zero. Any number that is greater than zero it will give the natural logarithm number. In order to make LN work, we need to give a number that is greater than zero.

By applying the formula in cell C2.

So the Result will be:

Similarly, it is applied to other cells in that column to get the desired output.

### Example #5

Natural logarithm number works exactly the opposite of exponential function. This function is the inverse of EXP function in excel where =EXP (1) is equal to 2.718282 and =LN (2.718282) is equal to 1.

By applying the formula

the output will be :

**Things to remember about LN Function in Excel**

- LN requires only positive numbers. The supplied number cannot be zero or negative.
- To get to know how LN works first you need to learn the basics of logarithms and refer logbooks.
- The supplied values should be a positive number and cannot supply any of the operators and symbol values. So cannot be a non-numeric value.
- The natural logarithm is related to EXP function. In EXP, we get the value if a base number is raised to an exponential number and in logarithm, we need to know the exponential number to get the desired number.

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