You can use the following formula in Excel to convert a 3-letter month abbreviation to a month number in Excel:

=MONTH(DATEVALUE(A2&1))

This particular formula converts the 3-letter month abbreviation in cell **A2** to a month number.

For example, if cell **A2** contains **Oct** then this formula will produce a value of **10**, since October is the 10th month.

The following example shows how to use this formula in practice.

**Example: Convert 3 Letter Month Abbreviation to Number in Excel**

Suppose we have the following column of 3-letter month abbreviations in Excel:

We can type the following formula into cell **B2** to convert the 3-letter month abbreviation in cell **A2** to a month number:

=MONTH(DATEVALUE(A2&1))

We can then drag and fill this formula down to each remaining cell in column B:

Column B now displays the month number for each 3-letter month abbreviation in column A.

**How This Formula Works**

Consider the formula that we used:

=MONTH(DATEVALUE(A2&1))

First, this formula uses **A2&1** to add a 1 to the end of the three-letter abbreviation.

For example, JAN becomes **JAN1**.

Next, the **DATEVALUE **function converts a text date to a serial number representing the number of days since Jan 1, 1900.

For example, **JAN1** becomes **44927** (the formula assumes the year being used is the current year) since Jan 1, 2023 is 44,927 days after Jan 1, 1900.

Lastly, the **MONTH** function extracts the month number from the serial number.

For example, the month number associated with the serial number 44927 is **1**.

**Note**: You can find the complete documentation for the **DATEVALUE** function in Excel here.

**Additional Resources**

The following tutorials explain how to perform other common tasks in Excel:

How to Convert Days to Months in Excel

How to Calculate Average by Month in Excel

How to Calculate the Number of Months Between Dates in Excel