The **LOG** function is categorized as a **Math & Trigonometry** function in Excel. Besides that, it is also a worksheet function; which means it can be used in combination with other functions in Excel. Moreover, this function is very simple and easy to use. This function is widely used in business analytics, statistics, and finance, etc. So, in this article, I am going to discuss the details of the** LOG **function and its application too.

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**Introduction to Excel LOG Function**

**Summary**

Returns the logarithm of a number to the base you specify. According to mathematics, the logarithm is the inverse to exponentiation. That means the logarithm of any given number is the exponent to which the base has to be raised to get a specified number. For instance, if **x **is the exponent of base** b** to get the value **y**.

**b**^{x}**=y **Then **log**_{b}**y=x**

**Syntax**

**LOG(number, [base])**

**Arguments**

Arguments | Requirement | Explanations |
---|---|---|

number |
Required | The positive real number for which we want the logarithm (e.g. 64, 8, 2.1, etc.). This value is numeric and must be greater than zero. |

base |
Optional | This base is used to calculate the logarithm of a number. If this parameter is omitted, the function will use a base of 10. |

**Return Value**

The **LOG** function returns a numeric value.

**Available in Version**

Excel for Office 365, Excel 2019, Excel 2016, Excel 2013, Excel 2011 for Mac, Excel 2010, Excel 2007, Excel 2003, Excel XP, Excel 2000.

**5 Examples to Use Excel LOG Function**

**1. Apply Excel LOG Function Without Base ArgumentÂ **

When the second argument of the **LOG** function: **[base] **is not supplied, the function assumes the base value as **10 **automatically. For example, we will find the logarithm of **10000**. So, follow the below steps to get the result:

**Steps:**

- First, type the following formula in
**Cell D5**.

`=LOG(B5)`

- As a consequence, you will get the logarithm value for
**10000**; which is**4**.

Here, Excel calculates the logarithm value and returns as** 4**. It means the number **10** is multiplied** 4** times to get **10000 **(**10*10*10*10**).

- Next, use the
**Fill Handle**(**+**) tool to copy the formula to the rest of the cells to get the logarithm value.

- Finally, here is the result for the rest of the cells.

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

**2. Use LOG Function With Base Argument in Excel**

Unlike **Method 1**, in this example, we will apply both arguments of the **LOG **function. Such as, we will find the logarithm value for **125 **with the base value of **5.**

**Steps:**

- Initially, type the below formula in
**Cell D5**.

`=LOG(B5,C5)`

- As a result, you will find that the logarithm value is
**3**.

Here, the result means base **5** raised to power **3** to get **125**.

- Lastly, for the rest of the cells use the
**Fill Handle (+)**to copy the formula.

**3. Put Decimal Value as Base Argument**

You can use variations in using the options **[base]** value. For instance, you can use decimal values as base values. In this method, we will find out the logarithm of **10**, for the base value of **.25**. So, follow the steps associated with the method.

**Steps:**

- In the beginning, type the following formula in
**Cell D5**.

`=LOG(B5,C5)`

- Consequently, you will find the below result.

Here, the function calculates the logarithm for 10 with base value: **.25** and returns **-1.660964047**. It means _{.25}**-1.660964047=10**, and** Log**_{.25}**(10)** **= -1.660964047**.

- At last, use the
**Fill Handle (+)**to copy the formula to the rest of the cells.

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**4. Use VBA to LOG Function**

Now we will use the** VBA** to get the logarithm for a particular number with a base value. For instance, we will find out the logarithm of **216** with the base value of** 6**. So, here are the steps associated with the process:

**Steps:**

- First, go to the worksheet containing the data and right-click on the sheet name. Next, click on the
**View Code.**

- Now, the
**Code Module**window will show up. Then, write the below code on the module.

```
Option Explicit
Function LogAny(b As Double, y As Double) As Double
Â Â Â Â ' b: base y: a given number
Â Â Â Â LogAny = Log(y) / Log(b)
End Function
Sub Log_VBA()
Â Â Â Â MsgBox LogAny(6, 216)
End Sub
```

- After that,
**Run**the code.

- In conclusion, you will see that the formula returns
**3**in the message box.

**5. Application of LOG and POWER Functions in Excel**

**The POWER function** is the inverse of the** LOG **function. For instance, we have a base value of **5** and exponent **3**. So, we will follow the below steps to get the logarithm associated with the previously mentioned base and exponent value using both the **POWER** and **LOG **functions.

**Steps:**

- First, type the below formula to
**Cell C7**.

`=LOG(POWER(C5,C6),C5)`

Here, the **POWER** function returns the result of a number raised to a power. The **POWER** formula will return **125**. Later, we passed the **POWER** function to the **LOG **function to get the logarithm of **125** with the base **5**.

- In the end, you will get the exponent
**3**, using the combination of functions.

**LOG Function Errors**

Although the** LOG function** is very easy to use, it returns errors at times. Such as, if you do not enter the base value properly, the function will return the following errors.

**#NUM!**: It happens when the**[base]**is negative or zero, then the function returns this error.

**#VALUE!**: If the**[base]**argument is non-numeric.

**#DIV/0!**: This occurs when the**[base]**argument is supplied as**1**.

**Conclusion**

In the above article, I have tried to discuss the methods elaborately. Hopefully, these methods and explanations will be enough to solve your problems. Please let me know if you have any queries.