EOMONTH / NETWORKDAYS — Excel guide
Business-calendar math: month ends, working days, and precise date differences — the functions behind due dates, SLAs, and tenure.
EOMONTH
The last day of a month, offset by any number of months.
- First of this month: EOMONTH(A2, -1) + 1.
- EDATE keeps the DAY while jumping months — subscriptions and maturities; EOMONTH snaps to month-END.
NETWORKDAYS
Count working days between two dates, holidays optional.
- BOTH endpoints count (Mon→Fri = 5). WORKDAY, its inverse, does NOT count the start day.
- Reversed arguments return a NEGATIVE count — no error.
- The .INTL variants take a weekend mask ("0000110") for Sun–Thu work weeks.
DATEDIF
Complete years/months/days between dates — the hidden function.
- Missing from autocomplete but real. Units: "y", "m", "d", plus remainders "ym" and "md" for '3 years, 7 months' strings.
- YEARFRAC gives the FRACTIONAL years between dates — interest accruals, proration (mind its day-count basis argument).