How to use the MONTH function

What is the MONTH function?

The MONTH function returns a number representing the month from an Excel date.

• 1 - January
• 2 - February
• 3 - March
• 4 - April
• 5 - May
• 6 - June
• 7 - July
• 8 - August
• 9 - September
• 10 - October
• 11 - November
• 12 - December

1. Introduction

What is an Excel date?

Dates are stored numerically but formatted to display in human-readable date/time formats, this enables Excel to do work with dates in calculations.

For example, dates are stored as sequential serial numbers with 1 being January 1, 1900 by default. The integer part (whole number) represents the date the decimal part represents the time.

This allows dates to easily be formatted to display in many date/time formats  like mm/dd/yyyy, dd/mm/yyyy and so on and still be part of calculations as long as the date is stored numerically in a cell.

You can try this yourself, type 10000 in a cell, press CTRL + 1 and change the cell's formatting to date, press with left mouse button on OK. The cell now shows 5/18/1927.

Why are dates actually integers in Excel?

This allows for calculations like adding or subtracting days to a given date. It also allows for easy formatting meaning you can customize the look of a given date by formatting the cell to your needs.

2. Syntax

MONTH(serial_number)

serial_number

Required. The date value you want to extract the month from.

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3. Example

The first example is in cell B3, it contains: 6/12/2023 which is an Excel date formatted like this mm/dd/yyyy. mm is the month number, dd is the day number, and yyyy is the four digit year in the Excel date.

Formula in cell C3:

The formula in cell C3 returns 6 which represents month "June". If we look at cell B3 we can see that 6 in 6/12/2023 is the month number.

The second example is in cell B4 which contains 3/13/2022.

Formula in cell C4:

The formula in cell C4 returns 3 which corresponds to month "March" which is the third month in a year.

The third example is in cell B5 which contains 10/14/2025.

Formula in cell C5:

The formula in cell C5 returns 10 which corresponds to month "October" which is the tenth month in a year.

To understand the MONTH function I need to explain that it needs an Excel date in order to calculate the month properly.  The date in cell B3 is an Excel date meaning it is a number formatted as a date. 1 is 1/1/1900 and 1/1/2000 is 36526 meaning there are 36526 days between the dates.

You can verify this, select a cell containing 1/1/2000 and press CTRL + 1 to open the "Format Cells" dialog box.

The "Sample" shown in the image above demonstrates what the value changes to if you choose to format the cells using the category "General". The sample contains 36526 which is the number representing 1/1/2000.

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4. MONTH Function alternative

The MONTH function returns a number that represents the month in a year based on a given date. The TEXT function allows you to format a string based on a given formatting code which is m, mm, mmm or mmmm. The differences between these codes are:

• m - month number without a leading zero. For example 6
• mm - month number with leading zero if smaller than 10. Based on the example in cell C3: 06
• mmm - the three first letters in the month name, for example, "Jun" which represents "June". Based on the example in cell C3: "Jun"
• mmm - the entire month name. Based on the example in cell C3: "June"

The example in cell C3 shows 6 based on date 6/12/2023, however, the output is different than the MONTH function. The output is a text string in contrast to the MONTH function which returns a number.

Formula in cell C3:

The formula in cell C3 returns "3", the double quotes represent that the output being a text string.

Explaining formula

Step 1 - TEXT function

The TEXT function lets you format values.

TEXT(value, format_text)

value - The string you want to format. You can use a cell reference here or use a text string.

format_text - Formatting code allowing you to change the way, for example, a date or a number is displayed to the Excel user.

Step 2 - Populate arguments

The TEXT function has two arguments.

value - B3

format_text - "m"

"m" is an abbreviation for month. A single "m" returns the number representing the position of a given month in a year.

Check out this article to learn more about formatting codes in the TEXT function.

Step 3 - Evaluate TEXT function

TEXT(B3, "m")

becomes

TEXT(45089, "m")

and returns 6. 6 represents the sixth month in a year which is "June".

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5. MONTH function - return month name instead of a number

5.1 Example 1 - INDEX function

Formula in cell C3:

Explaining formula in cell C3

Step 1 - Calculate month number

MONTH(B3)

• 1 - January
• 2 - February
• 3 - March
• 4 - April
• 5 - May
• 6 - June
• 7 - July
• 8 - August
• 9 - September
• 10 - October
• 11 - November
• 12 - December

MONTH(B3)

becomes

MONTH(45089)

and returns 6. Number 6 represents "June".

Step 2 - Return corresponding month name

The INDEX function returns a value in a cell range or array based on a row and column number (optional).

INDEX(array, [row_num], [column_num], [area_num])

INDEX({"January"; "February"; "March"; "April"; "May"; "June"; "July"; "August"; "September"; "October"; "November"; "December"},MONTH(B3))

becomes

INDEX({"January"; "February"; "March"; "April"; "May"; "June"; "July"; "August"; "September"; "October"; "November"; "December"}, 6)

and returns "June". "June" is the sixth month in a year.

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5.2 Example 2 - TEXT function

Formula in cell C4:

Explaining formula in cell C4

The TEXT function lets you format values.

TEXT(value, format_text)

value - The string you want to format. You can use a cell reference here or use a text string.

format_text - Formatting code allowing you to change the way, for example, a date or a number is displayed to the Excel user.

Formatting code "mmmm" evaluates to the month name.

TEXT(B4, "mmmm")

becomes

TEXT(44603, "mmmm")

and returns "March".

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5.3 Example 3 - Cell formatting

You can also show the month name using cell formatting, the image above demonstrates cell formatting applied to cell C5.

How to apply cell formatting:

1. Select cell C5.
2. Press CTRL + 1 to open the "Format Cells" dialog box.
3. Press with left mouse button on "Category" Custom, see the image above.
4. Enter mmmm below Type:
5. Press with left mouse button on OK button to apply cahnges.

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6. Filter dates based on month

Formula in cell D3:

Explaining formula

Step 1 - Calculate month number for each date value

MONTH(B3:B11)

becomes

MONTH({44667; 44667; 44700; 44707; 45006; 45051; 45054; 45075; 45079})

and returns {4; 4; 5; 5; 3; 5; 5; 5; 6}.

Step 2 - Compare month number to condition

The equal sign lets you check if values are equal, note that this does not perform a case-sensitive comparison. Check out the EXACT function if upper and lower letters matter.

MONTH(B3:B11)=5

becomes

{4; 4; 5; 5; 3; 5; 5; 5; 6}=5

and returns

{FALSE; FALSE; TRUE; TRUE; FALSE; TRUE; TRUE; TRUE; FALSE}

Step 3 - Extract dates meeting the condition

The FILTER function is a new function available to Excel 365 subscribers. It lets you extract values based on a condition or criteria.

FILTER(array, include, [if_empty])

FILTER(B3:B11, MONTH(B3:B11)=5)

becomes

FILTER({44667; 44667; 44700; 44707; 45006; 45051; 45054; 45075; 45079}, {FALSE; FALSE; TRUE; TRUE; FALSE; TRUE; TRUE; TRUE; FALSE})

and returns {44700; 44707; 45051; 45054; 45075}.

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7. MONTH Function not working

Check your spelling, the image above shows the MONTH function misspelled. An #NAME? error is shown in cell C3.

Cell B3 contains a text value and not a proper Excel date, this returns a #VALUE! error in cell C3.

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'MONTH' function examples

Functions in 'Date and Time' category

The MONTH function function is one of 22 functions in the 'Date and Time' category.

Excel function categories

Excel categories

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