How to show month name or number, get first or last day of month, and more Excel date formulas. Get the free workbook with examples.

To calculate the number of days between two specific dates, you don't need a special function -- just subtract the earlier date from the later date.

For example, with a start date in cell A2 and end date in cell B2, use this formula:

**=B2-A2**

NOTE: If the result looks like a date, instead of a number, change the cell's number format to General

If you subtract the later date from the earlier date, the result will be a negative number, and Excel cannot display the result

To calculate the the current date, use the TODAY function. It will automatically update, if you open the workbook on a different day.

**=TODAY()**

NOTE: To enter the current date as a static value, that will not update,
use the shortcut key: **Ctrl + ;**

If a cell contains a date and time, you can use the following functions to extract the year, month number, or day number from the date. In this example, the date is in cell A2.

Year: **=YEAR(A2)**

Month: **=MONTH(A2)**

Week: **= WEEKNUM(A2)**

Day: **= DAY(A2)**

NOTE: If the result looks like a date, instead of a number, change the cell's number format to General

If a cell contains a date, you can extract parts of that date as text. For example, show the month name, or the weekday name of the date. In this example, the date is in cell A2.

Month Name (short): **=TEXT(A2,"mmm") **

Month Name (long): **=TEXT(A2,"mmmm")**

Weekday Name (short): **=TEXT(A2,"ddd")**

Weekday Name (long): **=TEXT(A2,"dddd")**

If you need to calculate the first or last day of a month, the EOMONTH (end of month) function works well. In this example, the date is in cell B2.

The EOMONTH uses 2 arguments -- Start Date, and Number of Months. To get a date in the current month, use zero as the number of months.

Here are a few examples:

Last day of previous month: **=EOMONTH(B2,-1)**

First day of selected month: **=EOMONTH(B2),-1)+1 **

Last day of selected month: **=EOMONTH(B2,0)**

First day of next month: **=EOMONTH(B2,0)+**1

Last day of selected month, last year: **=EOMONTH(B2,-12)**

Or, combine the EOMONTH function with TODAY, to get dates relative to the current date. For example:

First day of current month: **=EOMONTH(TODAY(),-1)+1**

If a cell contains a combined date and time, you can extract just the date value, by using the INT function. Excel stores dates as numbers, with the integer representing the date, and a decimal portion representing the time.

The INT function returns just the integer portion of that number, which represents the date. In this example, the combined date/time is in cell A2.

To get the date, enter the following formula in cell B2: **=INT(A2)**

To get the weekday number for a date, use the WEEKDAY function. For example, with a date in cell B4, this formula will show its weekday number (Sunday = 1, Monday = 2, etc.):

**=WEEKDAY(B4)**

There is an optional second argument for the WEEKDAY function -- **return_type** -- which controls how the weekdays are numbered. The list of options is shown in the screen shot below.

- If this argument is omitted, the default return_type of 1 is used, with weekdays numbered from Sunday (1) to Saturday (7)
- In older versions of Excel, only options 1, 2 and 3 are available.

To get the week number for a date, use the WEEKNUM function. For example, with a date in cell B2, this formula will show its week number:

**=WEEKNUM(B2)**

There is an optional second argument for the WEEKNUM function -- **return_type** -- which controls how the weekdays are numbered. The list of options is shown in the screen shot below.

- If this argument is omitted, the default return_type of 1 is used, with weeks starting on Sunday
- In older versions of Excel, only options 1 and 2 are available.

There are two systems used for the week numbers -- System 1 and System 2. When you click on a Return Type in the list, you can see which system it uses.

**System 1** -- Week containing January 1 is the first week of the year, and is numbered week 1.

**System 2** -- Week containing first Thursday of year is first week of year, and is numbered as week 1. European week numbering system (ISO 8601)

To group data by week, use the WEEKDAY function to calculate a week start date for each record. In the screen shot below, there are dates in cells A2:A9. The first 7 dates are all in the same week, with a start date of Sunday, November 27. The final date is in the following week, which begins Sunday, December 4.

Use this formula to calculate Sunday as the start date: **=A2-WEEKDAY(A2+1,3)**

The "3" at the end of that formula tells Excel to use the numbers 0 - 6 for Monday to Sunday. The date is adjusted by one day, to subtract 0 if the date is a Sunday, 1 on Monday, etc.

When working with the GETPIVOTDATA formula, some fields might require date references. If the date format in the formula is not an exact match for the date format in the pivot table, the result might be an error.

To avoid this, you can use one of the Date workarounds that are described on the GETPIVOTDATA page.

To see how these formulas work, download the sample Date Functions workbook. The file is zipped, and is in xlsx file format

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Last updated: October 26, 2018 9:16 AM