NETWORKDAYS.INTL
Count true working days.
Why planners need it
Capacity, leave and ramp plans run on working days, not calendar days. This counts them and skips weekends and holidays you define.
Syntax
=NETWORKDAYS.INTL(start, end, [weekend], [holidays])
Worked example
Productive days in a month, excluding a bank-holiday list:
=NETWORKDAYS.INTL(start, end, 1, Holidays) → e.g. 21 days. The weekend code 1 = Sat+Sun; other codes handle 4-day weeks.
Watch out: Pass a holidays range or those days still count. Use the .INTL version for non-standard weekends (e.g. Fri/Sat).