The **LN** function in Excel is a **Math Function** that returns the **natural logarithm** of a number. Here is an overview:

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**Introduction to the LN Function**

**Objective: **To calculate the natural logarithm of a number.**Syntax: =LN(number)****Arguments: number-** that you want to calculate the natural logarithm of

**9 Examples of Using the LN Function in Excel**

**Integer Numbers:** In mathematics, integers are a set of **whole** numbers that can be **positive**, **negative**, or **zero**, but cannot be a **fraction**. **Read more**

**1. Find Out the Natural Logarithm of a Positive Integer Number Using the LN Function in Excel**

The integer numbers include **positive** whole numbers like 1,2,3,4, etc. Let’s compute the natural logarithm for them.

**How to Do:** In cell **E5 **put the following formula:

`=LN(2)`

**Result****:** The natural logarithm of positive integer **2** results as **0.69**

Similarly, we can get the natural logarithms of all positive integers as we did in the example for 3,4,5, and 10

**Read More: How to Use Excel LOG Function (5 Easy Methods)**

**2. Compute the Natural Logarithm of a Negative Integer Number**

The integer numbers include negative whole numbers like -1,-2,-3,-4, etc. let’s compute the natural logarithm for them.

**How to Do:** In cell **E5** put the following formula:

`=LN(-1)`

**Result****:** The natural logarithm of negative integer **-1** results in **#NUM! error.**

Similarly, as shown in the example, any negative number will result in **#NUM! error** in the **LN** function.

**Read More:** **51 Mostly Used Math and Trig Functions in Excel**

**3. Evaluate the Natural Logarithm of 0 by the LN Function**

Zero (0) is an integer number as we described before. Let’s evaluate the natural logarithm for zero.

**How to Do:** In cell **E5** put the following formula:

`=LN(0)`

**Result****:** The natural logarithm of **zero (0)** results in **#NUM! error. **

**Read More:** **44 Mathematical Functions in Excel (Download Free PDF)**

**4. Calculate the Natural Logarithm of a Fractional Number**

**Fractions****:** In Mathematics, fractions are defined as parts of whole numbers that can be both positive and negative. **Learn more**

**4.1 Natural Logarithm for a Positive Fractional Number**

**How to Do****:** In cell **E5** put the following formula:

`=LN(0.1)`

**Result****:** The natural logarithm of **0.1** is –2.30.

Similarly, we can see from the example that the natural logarithm of **positive fractional** numbers will result in negative fraction numbers.

**4.2 ****Natural Logarithm for a Negative Fractional Number**

**How to Do:** In cell **E8** put the following formula:

`=LN(0-.5)`

**Result****:** The natural logarithm of all **negative fractional number**s will result in **#NUM! error** as shown in the example.

**5. Use the LN Function to Calculate the Natural Logarithm of 1 **

**How to Do:** In cell **D5** put the following formula:

`=LN(1)`

**Result****:** The natural logarithm of **1** results in **0****.**

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**6. Natural Logarithm of 2.718 Using the LN Function in Excel **

The **LN** is a function that works opposite of the **EXP**** function**. In this example, we first calculated the **exponential** of **1 **and then used the **result** as input for the **LN function.**

**How to Do:**

- In the cell,
**D5**put the following formula:

`=EXP(1)`

- In
**D6**put**D5**as the input for the**LN**function, i.e.

` =LN(D5)`

**Result****:** The natural logarithm of **2.718** results in **1****.**

**Read More: How to Use Excel EXP Function (5 Examples)**

**7. Find Out the Natural Logarithm of a Non-numeric Value**

The LN function cannot evaluate a non-numeric value as it is a Mathematical function. Let’s dive into the example:

**How to Do:** In cell **E5** put the following formula:

`=LN(a)`

**Result****:** The natural logarithm of the non-numeric value **a** results in **#NAME? error.**

Similarly, any non-numeric values or a combination of number and non-numeric values results in **#NAME? or #VALUE! error.**

**8. Figure Out the Natural Logarithm of an Exponential Number Using the LN Function in Excel **

The **LN **function and the **EXP** function are **opposite** of each other. When we use the **EXP** function nested within the **LN** function it results in the **argument** of the EXP function itself.

See a bunch of examples in the screenshot below:

**9. Relation Between LN and LOG Function**

The **LN** function is a form of the **LOG** function that has **e** as its **base**. In this example, we’ll show how these two can be used alternately to get the same result.

**How to Do: **

- Put the following formula in cell E5

`=LOG(4,EXP(1))`

- In the next step, write the
**LN**function which takes**4**as its argument.

**Result****:** The **output** from both the formulas is **1.39** which confirms our previous statement.

**Read More: Exponential Notation E in Excel & How to Turn Off Auto Scientific Notation!**

**Things to Remember**

- The
**LN**function only allows**positive**numbers (whole or fractional) as arguments. -
**Negative whole**numbers,**negative fractional**numbers and**zero**will result in**#NUM!**error as they are considered**invalid arguments**for the**LN**function**.**

**Conclusion**

Now, we know how to use the LN function in Excel. Hopefully, it would encourage you to use this function more confidently. Any questions or suggestions don’t forget to put them in the comment box below