Summary

The Excel EOMONTH function returns the last day of the month before or after a given date.

EOMONTH is useful for month-end reporting, accounting cutoffs, billing periods, due dates, lease schedules, and any workbook that needs a clean month-end boundary.

Syntax

=EOMONTH(start_date, months)

start_date is the anchor date. months tells Excel how many months forward or backward to move before returning the month-end date.

Arguments

• start_date - The starting date for the calculation.
• months - The number of months to shift. Use 0 for the current month, positive values for future months, and negative values for past months.

EOMONTH vs EDATE

These functions both shift dates by months, but they do not return the same kind of result.

Use EOMONTH when you need the end of a month. Use EDATE when you want to preserve the day position as much as possible.

Using EOMONTH

EOMONTH is especially useful when dates arrive on many different days but your reporting needs a consistent month-end result. For example, invoices dated throughout May can all be converted to May 31 for monthly reporting.

The second argument controls the shift. A value of 0 keeps the current month, 1 moves to next month, and -1 moves to the previous month. Microsoft also notes that if months is not an integer, it is truncated.

A common pattern is DAY(EOMONTH(date,0)), which returns the total number of days in the month. That makes EOMONTH useful for monthly proration as well as reporting cutoffs.

Example 1 - Return the End of the Current Month

Use EOMONTH with a zero month offset to get the last day of the same month.

=EOMONTH(A1,0)

If A1 contains 2026-01-15, the result is the final day of January 2026.

Example 2 - Return the End of the Next Month

Change the month offset to move forward before taking the month end.

=EOMONTH(A1,1)

This returns the final day of the following month. It is useful for billing cycles, contract periods, and rolling schedules.

Example 3 - Count the Days in a Month

Wrap EOMONTH in DAY to get the total number of days in the target month.

=DAY(EOMONTH(A1,0))

This pattern automatically handles different month lengths and leap years, so it is useful for monthly calculations and proration logic.

Example 4 - Return the End of the Year

You can also combine EOMONTH with MONTH to jump to the final day of the year.

=EOMONTH(B1,12-MONTH(B1))

If B1 is any date in 2026, the result is December 31, 2026. This is a useful year-end cutoff pattern.

Conclusion Recap

• Summary: EOMONTH returns the last day of a month.
• Core use: Month-end reporting, accounting cutoffs, and billing boundaries.
• Month offset: Use positive, negative, or zero month shifts to move around the calendar.
• Helpful pattern: DAY(EOMONTH(date,0)) returns the number of days in a month.
• Difference from EDATE: EOMONTH returns a month-end date, while EDATE returns a shifted calendar date.
• Best practice: Use valid Excel dates for reliable results.