*The tutorial explains the nuts and bolts of Excel MONTH and EOMONTH functions. You will find an array of formula examples demonstrating how to extract month from date in Excel, get the first and last day of the month, convert month name to number and more.*

In the previous article, we explored a variety of Excel functions to work with weekdays and days of year. Today, we are going to operate on a bigger time unit and learn the functions that Microsoft Excel provides for months.

In this tutorial, you will learn:

Microsoft Excel provides a special MONTH function to extract a month from date, which returns the month number ranging from 1 (January) to 12 (December).

The MONTH function can be used in all versions of Excel 2016 - 2000 and its syntax is as simple as it can possibly be:

MONTH(serial_number)

Where `serial_number`

is any valid date of the month you are trying to find.

For the correct work of Excel MONTH formulas, a date should be entered by using the DATE(year, month, day) function. For example, the formula `=MONTH(DATE(2015,3,1))`

returns 3 since DATE represents the 1st day of March, 2015.

Formulas like `=MONTH("1-Mar-2015")`

also work fine, though problems may occur in more complex scenarios if dates are entered as text.

In practice, instead of specifying a date within the MONTH function, it's more convenient to refer to a cell with a date or supply a date returned by some other function. For example:

`=MONTH(A1)`

- returns the month of a date in cell A1.

`=MONTH(TODAY())`

- returns the number of the current month.

At first sight, the Excel MONTH function may look plain. But look through the below examples and you will be amazed to know how many useful things it can actually do.

There are several ways to get month from date in Excel. Which one to choose depends on exactly what result you are trying to achieve.

**MONTH function in Excel - get month number from date.**This is the most obvious and easiest way to convert date to month in Excel. For example:

`=MONTH(A2)`

- returns the month of a date in cell A2.`=MONTH(DATE(2015,4,15))`

- returns 4 corresponding to April.`=MONTH("15-Apr-2015")`

- obviously, returns number 4 too.

**TEXT function in Excel - extract month as a text string.**An alternative way to get a month number from an Excel date is using the TEXT function:

`=TEXT(A2, "m")`

- returns a month number without a leading zero, as 1 - 12.`=TEXT(A2,"mm")`

- returns a month number with a leading zero, as 01 - 12.

Please be very careful when using TEXT formulas, because they always return month numbers as text strings. So, if you plan to perform some further calculations or use the returned numbers in other formulas, you'd better stick with the Excel MONTH function.

The following screenshot demonstrates the results returned by all of the above formulas. Please notice the right alignment of numbers returned by the MONTH function (cells C2 and C3) as opposed to left-aligned text values returned by the TEXT functions (cells C4 and C5).

In case you want to get a month name rather than a number, you use the TEXT function again, but with a different date code:

`=TEXT(A2, "mmm")`

- returns an abbreviated month name, as Jan - Dec.`=TEXT(A2,"mmmm")`

- returns a full month name, as January - December.

If you don't actually want to convert date to month in your Excel worksheet, you are just wish to **display a month name** only instead of the full date, then you don't want any formulas.

Select a cell(s) with dates, press Ctrl+1 to opent the *Format Cells* dialog. On the *Number* tab, select **Custom** and type either "mmm" or "mmmm" in the **Type** box to display abbreviated or full month names, respectively. In this case, your entries will remain fully functional Excel dates that you can use in calculations and other formulas. For more details about changing the date format, please see Creating a custom date format in Excel.

Suppose, you have a list of numbers (1 through 12) in your Excel worksheet that you want to convert to month names. To do this, you can use any of the following formulas:

**To return an abbreviated month name (Jan - Dec).**`=TEXT(A2*28, "mmm")`

`=TEXT(DATE(2015, A2, 1), "mmm")`

**To return a full month name (January - December).**`=TEXT(A2*28, "mmmm")`

`=TEXT(DATE(2015, A2, 1), "mmmm")`

In all of the above formulas, A2 is a cell with a month number. And the only real difference between the formulas is the month codes:

- "mmm" - 3-letter abbreviation of the month, such as Jan - Dec
- "mmmm" - month spelled out completely
- "mmmmm" - the first letter of the month name

When used together with month format codes such as "mmm" and "mmmm", Excel considers the number 1 as Day 1 in January 1900. Multiplying 1, 2, 3 etc. by 28, you are getting Days 28, 56, 84, etc. of the year 1900, which are in January, February, March, etc. The format code "mmm" or "mmmm" displays only the month name.

There are two Excel functions that can help you convert month names to numbers - DATEVALUE and MONTH. Excel's DATEVALUE function converts a date stored as text to a serial number that Microsoft Excel recognizes as a date. And then, the MONTH function extracts a month number from that date.

The complete formula is as follows:

`=MONTH(DATEVALUE(A2 & "1"))`

Where A2 in a cell containing the month name you want to turn into a number (&"1" is added for the DATEVALUE function to understand it's a date).

The EOMONTH function in Excel is used to return the last day of the month based on the specified start date. It has the following arguments, both of which are required:

EOMONTH(start_date, months)

**Start_date**- the starting date or a reference to a cell with the start date.**Months**- the number of months before or after the start date. Use a positive value for future dates and negative value for past dates.

Here are a few EOMONTH formula examples:

`=EOMONTH(A2, 1)`

- returns the last day of the month, one month after the date in cell A2.

`=EOMONTH(A2, -1)`

- returns the last day of the month, one month before the date in cell A2.

Instead of a cell reference, you can hardcode a date in your EOMONTH formula. For example, both of the below formulas return the last day in April.

`=EOMONTH("15-Apr-2015", 0)`

`=EOMONTH(DATE(2015,4,15), 0)`

To return the **last day of the current month**, you use the TODAY() function in the first argument of your EOMONTH formula so that today's date is taken as the start date. And, you put 0 in the `months`

argument because you don't want to change the month either way.

`=EOMONTH(TODAY(), 0)`

And here are the results returned by the Excel EOMONTH formulas discussed above:

If you want to calculate how many days are left till the end of the current month, you simply subtract the date returned by TODAY() from the date returned by EOMONTH and apply the General format to a cell:

`=EOMONTH(TODAY(), 0)-TODAY()`

As you already know, Microsoft Excel provides just one function to return the last day of the month (EOMONTH). When it comes to the first day of the month, there is more than one way to get it.

If you have the month number, then use a simple DATE formula like this:

=DATE(*year*, *month number*, 1)

For example, =DATE(2015, 4, 1) will return 1-Apr-15.

If your numbers are located in a certain column, say in column A, you can add a cell reference directly in the formula:

`=DATE(2015, B2, 1)`

If you want to calculate the first day of the month based on a date, you can use the Excel DATE function again, but this time you will also need the MONTH function to extract the month number:

=DATE(*year*, MONTH(*cell with the date*), 1)

For example, the following formula will return the first day of the month based on the date in cell A2:

`=DATE(2015,MONTH(A2),1)`

When your calculations are based on today's date, use a liaison of the Excel **EOMONTH** and TODAY functions:

`=EOMONTH(TODAY(),0) +1`

- returns the 1^{st} day of the following month.

As you remember, we already used a similar EOMONTH formula to get the last day of the current month. And now, you simply add 1 to that formula to get the first day of the next month.

In a similar manner, you can get the first day of the previous and current month:

`=EOMONTH(TODAY(),-2) +1`

- returns the 1^{st} day of the previous month.

`=EOMONTH(TODAY(),-1) +1`

- returns the 1^{st} day of the current month.

You could also use the Excel **DATE** function to handle this task, though the formulas would be a bit longer. For example, guess what the following formula does?

`=DATE(YEAR(TODAY()), MONTH(TODAY()), 1)`

Yep, it returns the first day of the current month.

And how do you force it to return the first day of the following or previous month? Hands down :) Just add or subtract 1 to/from the current month:

To return the first day of the following month:

`=DATE(YEAR(TODAY()), MONTH(TODAY())+1, 1)`

To return the first day of the previous month:

`=DATE(YEAR(TODAY()), MONTH(TODAY())-1, 1)`

In Microsoft Excel, there exist a variety of functions to work with dates and times. However, it lacks a function for calculating the number of days in a given month. So, we'll need to make up for that omission with our own formulas.

If you know the month number, the following DAY / DATE formula will return the number of days in that month:

=DAY(DATE(*year*, *month number* + 1, 1) -1)

In the above formula, the DATE function returns the first day of the following month, from which you subtract 1 to get the last day of the month you want. And then, the DAY function converts the date to a day number.

For example, the following formula returns the number of days in April (the 4^{th} month in the year).

`=DAY(DATE(2015, 4 +1, 1) -1)`

If you don't know a month number but have any date within that month, you can use the YEAR and MONTH functions to extract the year and month number from the date. Just embed them in the DAY / DATE formula discussed in the above example, and it will tell you how many days a given month contains:

`=DAY(DATE(YEAR(A2), MONTH(A2) +1, 1) -1)`

Where A2 is cell with a date.

Alternatively, you can use a much simpler DAY / EOMONTH formula. As you remember, the Excel EOMONTH function returns the last day of the month, so you don't need any additional calculations:

`=DAY(EOMONTH(A1, 0))`

The following screenshot demonstrates the results returned by all of the formulas, and as you see they are identical:

In a large table with lots of data, you may often need to get a sum of values for a given month. And this might be a problem if the data was not entered in chronological order.

The easiest solution is to add a helper column with a simple Excel MONTH formula that will convert dates to month numbers. Say, if your dates are in column A, you use =MONTH(A2).

And now, write down a list of numbers (from 1 to 12, or only those month numbers that are of interest to you) in an empty column, and sum values for each month using a SUMIF formula similar to this:

`=SUMIF(C2:C15, E2, B2:B15)`

Where E2 is the month number.

The following screenshot shows the result of the calculations:

If you'd rather not add a helper column to your Excel sheet, no problem, you can do without it. A bit more trickier SUMPRODUCT function will work a treat:

`=SUMPRODUCT((MONTH($A$2:$A$15)=$E2) * ($B$2:$B$15))`

Where column A contains dates, column B contains the values to sum and E2 is the month number.

Now that you know how to use the Excel MONTH and EOMONTH functions to perform various calculations in your worksheets, you may take a step further and improve the visual presentation. For this, we are going to use the capabilities of Excel conditional formatting for dates.

In addition to the examples provided in the above mentioned article, now I will show you how you can quickly highlight all cells or entire rows related to a certain month.

In the table from the previous example, suppose you want to highlight all rows with the current month dates.

First off, you extract the month numbers from dates in column A using the simplest =MONTH($A2) formula. And then, you compare those numbers with the current month returned by =MONTH(TODAY()). As a result, you have the following formula which returns TRUE if the months' numbers match, FALSE otherwise:

`=MONTH($A2)=MONTH(TODAY())`

Create an Excel conditional formatting rule based on this formula, and your result may resemble the screenshot below (the article was written in April, so all April dates are highlighted).

And here's another challenge. Suppose you want to highlight the major holidays in your worksheet regardless of the year. Let's say Christmas and New Year days. How would you approach this task?

Simply use the Excel DAY function to extract the day of the month (1 - 31) and the MONTH function to get the month number, and then check if the DAY is equal to either 25 or 31, and if the MONTH is equal to 12:

`=AND(OR(DAY($A2)=25, DAY($A2)=31), MONTH(A2)=12)`

This is how the MONTH function in Excel works. It appears to be far more versatile than it looks, huh?

In a couple of the next posts, we are going to calculate weeks and years and hopefully you will learn a few more useful tricks. If you are interested in smaller time units, please check out the previous parts of our Excel Dates series (you will find the links below). I thank you for reading and hope to see you next week!

Excel formulas
CSV
Excel functions
Print
Vlookup in Excel
Merge data in Excel
SumIf
Excel CountIf
Excel Compare
Excel If statement
Excel Charts
Pivot Table
Updates
Excel conditional formatting
Excel formatting
Excel time
Excel duplicates
Excel date
Excel tips
Excel macro
Outlook
Google Sheets
Outlook duplicates
Outlook templates

## 180 Responses to "Using MONTH and EOMONTH functions in Excel - formula examples"

how calculate the sum 31 as a month or how to show 31 as (1 month or 1) in excel

i try =DATEDIF(0,F25,"ym") (where F25 is a no. or sum =31) but is show only 31 as result instead of 1.

if i have a sum or number like 28, 30 or 31 how i count these no. as 1 month

i try formula =DATEDIF(0,F26,"ym") but it show 0 and formula =DATEDIF(0,F26,"md") it show same no. as 28, 30 & 31.

i want it show as 1 month if any solution or formula pls.

I have dates in a row (dates span across months) and certain values in the cells below these dates (e.g. work shifts such as "M" for morning). I need to count number of occurrences of a shift per month. How to I achieve this ?

I tried using MONTH() and COUNTIF()/COUNTIFS() together but failed.

I have different dates in column A1 (1-Oct-19, 15-Oct-19,29-Oct-19, 12-Nov-19, 26-Nov-19, 10-Jan-21 and so on). I want to highlight only the current month in green and the rest of the month in the red. I mean before and after Jan in the red and Jan (Current Month) in green.

Example 1. Highlight dates within the current month

=MONTH($A2)=MONTH(TODAY())

Through this, if year changes it is highlighting the same month also. How can I highlight the date within the current month and year?

10-Jan-20, 15-Jan-21

It will highlight both cells. When the year is 2020, it should not highlight the year 2021.

Problem solved:

I used this-

=AND(MONTH($A1)=MONTH(TODAY()),YEAR($A1)=YEAR(TODAY()))

Problem solved:

I used this-

=AND(MONTH($A1)=MONTH(TODAY()),YEAR($A1)=YEAR(TODAY()))

Now I want the rest of the date should be highlighted in yellow colour. I mean if the month and the year is less than or more than today's month and the year it should be highlighted in yellow colour.

hi

i have one question, i have the calendar in excel and i am entering holidays next to the particular date. when i change the month, how i can clear the my holiday entries automatically.

thanks

I am facing a problem that I am using to display a stacked bar chart with "Time" as the timeline. However, I don't know how to make the x-axis (timeline) to display 1st day of each month. Any idea?

Hi,

Struggled to understand this, =TEXT(A2*28, "mmmm"). Why multiply by 28?

Hi Sam,

Thank you for a very good question!

In its internal system, Excel considers the number 1 as Day 1 in January 1900 (when used together with month format codes such as "mmm" and "mmmm"). By multiplying the numbers 1, 2, 3 etc. by 28, you are getting Days 28, 56, 84, etc. which are in January, February, March, etc. Multiplying by 29 will also work.

I've also added this explanation to the tutorial for other readers.

I have few date range with different months and year. I want to hight only date which are from January to June regardless year. Can you please help me for this?

Example.

04-12-2006

05-06-2007

20-08-2008

05-01-2009

09-11-2007

25-06-2008

08-01-2009

24-06-2008

01-02-2011

17-11-2011

24-09-2011

05-09-2012

30-09-2011

24-09-2011

04-07-2019

04-01-2009

31-12-2013

01-12-2013

01-12-2013

01-12-2013

22-01-2014

25-06-2008

01-12-2013

17-02-2012

01-12-2013

12-03-2016

12-03-2016

12-03-2016

12-03-2016

12-03-2016

12-12-2017

07-05-2019

10-07-2019

10-06-2019

05-07-2019

05-07-2019

29-07-2019

28-09-2019

from above dates I want to hightligh only dates from January to June regardless year.

01/01/2020 AMUH

02/01 DLD

03/01 AMUH

04/01 ARASH

05/01 DAFZA

02/02/2020 AMUH

04/02/2020 UTPM

01/03/2020 UPTM

07/03/2020 AMUH

04/04/2020 AMUH

HOW CAN WE CALCULATE MONT WISE

KINDLY SHOW THE CALCULATION

Thanks a lot for your information. I have an issue to convert the following text date to a real date type.

Jan 02, 2018

Would you help on how I can convert it to date type? I've tried "=date(RIGHT(A2,4) LEFT(A2,3) MID(A2,5,2))", but it doesn't work.

Hello? Mark!

Please use the following formula

=DATEVALUE(A2)

I need a formal that if a month has 31 days it will displace from cell D5 and if then displace from cell D4. the month is in A1. Can you help me, please?

Hello, Brenda!

If I understand your task correctly, the following formula should work for you:

=IF(DAY (EOMONTH (DATE(2020,A1,1),0)) = 31, D5, D4)

Hello,

I have calculated the number of year and months in excel. Now I am trying to get Excel to tell me what month and year that will be from now. For example, my car note will be paid off 2 years and 9 months from now, March 29, 2020. How can I get excel to tell me that 2 years and 9 months from now will be in December 2022? I thank you for your help with respect to resolving this issue in advance.

Hello Michael!

Please use the following formula

=DATE(YEAR(A1)+2, MONTH(A1)+9, DAY(A1)+0) or

=DATE(YEAR(TODAY())+2, MONTH(TODAY())+9, DAY(TODAY())+0)

We have a ready-made solution for your task. I'd recommend you to have a look at our Ablebits Tools - Date&Time Wizard.

This tool is available as a part of our Ultimate Suite for Excel that you can install in a trial mode and use for 30 days for free: https://www.ablebits.com/files/get.php?addin=xl-suite&f=free-trial

I need to take a date from this format 3/31/2020 to the "31st day of March 2020". I have NO problem on the March 2020 part but HOW in the world can I get the st part of 31st ??? Also need the abbreviations for all days 1, 2, 3, ..... 29, 30, and 31. Like 1st. 2nd, 3rd, and so on. The Only workaround I can think of is to create a table or chart with all the possible numbers with abbreviations and then use vlookup or the new xlookup.

Thanks in advance for any help or insight !!!

Hello Carl!

If I understand your task correctly, the following formula convert to ordinal date format:

=DAY(A1)&IF(OR(DAY(A1) = {1,2,3,21,22,23,31}),CHOOSE (1*RIGHT(DAY(A1),1),"st ","nd ","rd "),"th")&TEXT(A1,"mmmm, yyyy")

or

=DAY(A1)&IF(OR(DAY(A1) = {1,2,3,21,22,23,31}),CHOOSE (1*RIGHT(DAY(A1),1),"st day of ","nd day of ","rd day of "),"th day of ")&TEXT(A1,"mmmm, yyyy")

I hope it’ll be helpful.

I have downloaded a data which is from Jan-2020 to mar 2020, like below:

05/02/2020 06:09 - It is showing month as May

1/31/2020 2:55 AM - This one is showing Jan

1/29/2020 12:27 AM

1/17/2020 6:47 AM

1/16/2020 5:39 AM

1/14/2020 7:46 AM

06/01/2020 03:41 - This one showing as June 20202.

I tried converting it into month through text formula, tried changing format through data tab to convert text to column, also manually tried custom formatting but no go.

Please help me in rectifying this.

Hello Himanshu!

Please go to Format Cells, choose Number -> Custom Format and set

mmm-yyyy;@

to display the date as Jan 2020,

mmmm;@

to display the date as January.

I hope you will find my advice helpful.

I use a spreadsheet for monthly budget reports. Each month has a YTD column. The formula typically looks like this: ='[March 2019]MARCH 2019'!E3+'APRIL 2019'!B3

In this example, April is added to March's YTD totals in that column. When setting up the sheet for 2020, I have been unable to get it to change the whole column of totals. It will only change one cell at a time although I have included all cells.

Hello Gojo!

Unfortunately, you have not written what you managed to change in your formula and what you did not manage to change. It is not clear enough what exactly is not working.

Perhaps, there is a problem with the names of the files in your formula, but it is merely my assumption.

Please describe your problem in more detail and I will try to help you.

By using countif() I derive the total number of records of each branch as usual I want data regards specific month

Hello Madhavi!

Use the expression as a condition: MONTH(D1)=4 where D1 is the date cell.

For me to be able to help you better, please describe your task in more detail. It’ll help me understand it better and find a solution for you. Thank you.

Hi Alexander

This was very helpful for my first part of the task. I have now taken the month from a date and shown it as the Month in text. I now want to take that result and have it sequence monthly for 24 months across a row, but I am having trouble reference that result and indexing it across the columns. Can you advise?

I am a beginner in Excel, so trying to learn what I can as I need it.

Thank you!

Hello Glenn!

If I understand your task correctly, in cell A1 is your start date. In cell A2, write the formula

=TEXT(EDATE($A$1,COLUMN()-1), "mmmm")

After that you can copy this formula right along the row.

If there is anything else I can help you with, please let me know.

Hi Alexander,

I want to know the formula to get the particular day of every month in the given data.

Hello Vaibhav!

I think you need to read an article on our blog about WEEKDAY, DAY and other functions to calculate days in Excel

Currently using this [WEEKNUM(TODAY(), 1)-WEEKNUM(DATE(YEAR(TODAY()), MONTH(TODAY()), 1), 1)+1)] in a countif formula. However what would would i do if i wanted to have a month to date look. Ex Week 1 would just be week 1. and week 2 it would be week one + week two and so on.

Hello!

Your formula calculates the week number in the current month. But I don’t understand what else do you want to calculate? Explain in more detail so that I can help you.

Hi alexander,

Correct. Its currently calculating to look at the current week. IN my scenario I have bunch of dates all throughout the Month. And depending on the week i am in, i calculate how many of those dates fall within the same week that were are in. What i am wanting to do is to adjust that to give me a running total. For example, if i was in week 2 the current formula will just looks at all the dates that are in the second week and count those. Instead I'm wondering if we could alter the formula to look at all the past weeks of the month as well. So if we are in week 2, the formula would Look at week 2 + week 1. I hope i was able to clarify this.

Hello

If I understand your task correctly , if the date is written in cell C1, and the formula

= WEEKNUM (C1,1) -WEEKNUM (DATE (YEAR (C1), MONTH (C1), 1), 1) +1

in cell D1,

then the condition for the counter of the desired dates

= COUNTIFS($D$1:$D$99, D1) + COUNTIFS($D$1:$D$99, D1-1)

I hope this will help, otherwise please do not hesitate to contact me anytime.

I am a registered dog breeder and I would like to create in excel a schedule for the litter. I cannot breed two litters in 18 months. How do input my last litter so when I look at it when the right month and year to breed her. I only have 3 dogs.if it's under this month, to show in red. Anyone can help?

Hello!

I’m sorry but your task is not entirely clear to me. You need to use conditional formatting. What data do you use in the table?

For me to be able to help you better, please describe your task in more detail. It’ll help me understand it better and find a solution for you. Thank you.

I need a format for if a date has is in the last month to return another cell and if its not in the past month to return blank

Hello Ben!

Using cell formatting, your problem cannot be solved. If you need a formula, describe in more detail all the conditions. Please describe your problem in more detail. It’ll help me understand it better and find a solution for you. Thank you.

hello. i have a question and it may be stupid if this doesn't exist in excel. :D

is there a command/formula to change all the written month (ex: January) and change it to the next month (ex: February) rather than changing/typing it one by one. i wanted to make the changes faster since the 2 sheet file will be used for the entire year except the months have to be changed.

thank you for your time. :)

I am doing a monthly billing spreadsheet where I have listed income by each month, this is along side the bill,amount, and due date. At the bottom I am wanting the extra money left from each month calculation, needing it to register which month it is and bring that months income amount - the current months bills. Example below.

Due Date Bills Amount Month Wks Income(mthly)

7th Car $365 January 4 $2000

8th Netflix $13 February 4 $2000

Total Monthly Expenses $478 Leftover ____?????_____

Hello LeAnn !

I’m sorry but your task is not entirely clear to me. For me to be able to help you better, please describe your task in more detail. Please specify what you were trying to find, what formula you used and what problem or error occurred.How is 478 calculated? Give more an example of the source data and the expected result.

It’ll help me understand it better and find a solution for you. Thank you.

in case if you got 00 your computer's language setup is the problem

use this: =TEXT(A1;"[$-en-EN]HHHH")

en-EN ---> add here the language's code you want to see

HHHH ---> the version of MMMM (month full lenght) in your computer's language

Your version can be checked in Format Cells - Custom ---> last two options

Hello,

I have used the formula above and only changed the cells, however the result sum to $0. Do the cells need to be together to work because these are not.

Thankyou

Hello Mark!

The formula is spelled correctly. But you asked your question in the wrong article. I recommend that you study this instruction about the SUMIF function.

Sry I forgot to add the formula I'm using. =SUMIF(O6:O24, AN6, AJ6:AJ24)

Hi Alexander,

I have data as below:

Task start_day end_day duration, d

Task1 01/03/2020 15/05/2020 55

I have to show task duration by month in the chart. How can I get data needed for chart? I need: Martch duration = 20 days, April duration = 20 days, May duration = 15 days. Thanks.

Hello Ruta!

I’m sorry but your task is not entirely clear to me.

Please describe your problem in more detail. Include an example of the source data and the result you want to get. It’ll help me understand your request better and find a solution for you. Thank you.

Correction: Martch duration = 22 days, April duration = 22 days, May duration = 11 days. Thanks.

Hi,

I need your help.

Column A = Completion of project (Date format: 01-Jul-2020)

Column B = Invoicing Month (Month format: July 2020)

Items completed within 1st - 25th of every month must be invoiced in that month itself and items completed from 26th-31st is to be invoiced the next month.

Any ideas how I can set a rule so Column B is generated based on the dates automatically?

Hello Sammy!

The formula below will do the trick for you:

=IF(DAY(A1)<26,A1,EOMONTH(A1,0)+1)

Remember to set the date format in cell B correctly