A date in Excel is a number underneath. The date functions pull out the part you need, such as the month, so you can group and summarise data in reports.
YEAR, MONTH and DAY
If A2 has 15-Mar-2026:
=YEAR(A2)returns 2026.=MONTH(A2)returns 3.=DAY(A2)returns 15.
Month name and day name with TEXT
=TEXT(A2, "mmm") returns Mar and =TEXT(A2, "mmmm") returns March. =TEXT(A2, "dddd") returns the day name, such as Sunday.
WEEKDAY
=WEEKDAY(A2, 2) returns 1 for Monday up to 7 for Sunday. The second argument 2 makes Monday the first day. To flag weekends: =IF(WEEKDAY(A2,2)>5, "Weekend", "Weekday").
Build a date from parts
=DATE(2026, 3, 15) creates a real date. It is useful when year, month and day sit in three separate columns.
Group sales by month
Add a helper column =TEXT(A2,"yyyy-mm") and use it in a pivot table or SUMIFS. The year-month format sorts correctly, which month names alone do not.
Common mistakes
- A date typed as text gives #VALUE!. Check that it is right aligned.
- Different regional settings read 03/04/2026 as 3 April or 4 March. Use the DATE function to avoid doubt.