Number of days between 2 dates excluding weekends

You can use the NETWORKDAYS.INTL function if you want to return the total number of business days between two dates excluding weekends and public holidays
You can use the WORKDAY.INTL function if you want to return the serial number for a given number of working days before or after a date.

1 - Displays the current date. Custom format "dddd dd mmmm yyyy".
2 - Displays the current date and time. Custom format "dddd dd mmmm yyyy hh:mm:ss".

Built-in Functions

NETWORKDAYS.INTL - The total number of working days between two dates excluding weekends and holidays.
WORKDAY.INTL - The date serial number that is a given number of working days before or after a date.

Related Formulas

Number of days between 2 dates
Number of Mondays between 2 dates
Number of days in a particular month
Number of days in a particular year