EOMONTH Function: syntax, examples, mistakes and translation notes
Returns the last day of a month offset.
Syntax
=EOMONTH(start_date, months)
Arguments
start_date
Valid date value to start from.
months
Whole-month offset; 0 means the same month.
Worked examples
=EOMONTH(DATE(2026,9,12),0)
Returns the last day of September 2026.
=EOMONTH(A2,1)
Returns the last day of the month after A2.
Practical tips
- Use 0 for the end of the current month.
- Add 1 to EOMONTH(A2,-1) to get the first day of A2’s month.
- Keep start_date as a true date value, not ambiguous text.
Common mistakes
- Supplying text that looks like a date but is not parsed consistently.
- Forgetting that the result may display as a serial number if the cell is not date-formatted.
Related functions
Frequently asked questions
What does EOMONTH do?
Returns the last day of a month offset.
Why might a EOMONTH formula return an unexpected result?
Supplying text that looks like a date but is not parsed consistently. Start by testing the smallest referenced range or condition independently before adding wrappers or fallbacks.
Check the complete formula
Function syntax is only one part of a working workbook. Paste the finished expression into the Formula Checker for structural warnings, the Formatter for readability or the Translator when a supported locale mapping is involved.
Testing note: examples are educational. Spreadsheet versions, locale settings, tables, named ranges and workbook data can change behavior, so validate important formulas with representative data.