What DATE does
DATE combines year, month, and day values into a real Excel date. It is often safer than typing date text directly because it avoids ambiguity across locales and formats.
Practical examples
Build a date from separate cells
=DATE(A2,B2,C2)
This is useful when raw data stores years, months, and days in separate columns.
Find the last day of the previous month
=DATE(YEAR(A2),MONTH(A2),0)
Because Excel normalizes day values, day 0 rolls back to the prior month's final day.
Common mistakes and notes
DATE returns a number underneath
If the result looks like a serial number, the cell likely needs date formatting.
DATE handles overflow and underflow
Month values above 12 or day values outside the normal range roll into adjacent months automatically. That is powerful, but it can also conceal bad inputs.