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

**Introduction to the LN Function**

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

**How to Use the LN Function in Excel: 9 Examples**

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

**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. Letâ€™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 10Â Â

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

The integer numbers include negative whole numbers like -1,-2,-3,-4, etc. letâ€™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 inÂ **#NUM! error.**

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

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

Zero (0) is an integer number as we described before. Letâ€™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 inÂ **#NUM! error.Â Â **

**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.

**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 â€“2.30.

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

**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 inÂ **#NUM! error** as shown in the example.Â

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

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

`=LN(1)`

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

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

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.

`Â =LN(D5)`

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

**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. Letâ€™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 inÂ **#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 ExcelÂ **

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.Â

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, weâ€™ll show how these two can be used alternately to get the same result.

**How to Do:Â **

- 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.Â

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

**Things to Remember**

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

**Download the Practice Workbook**

Download this practice workbook to exercise while you are reading this article.

**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 donâ€™t forget to put them in the comment box below.