In Excel, subtracting an Earlier Date from a Later Date will calculate the number of Days in between – which can be very useful.
However, we may need to calculate the number of Working Days between two Dates. If that is the case then NETWORKDAYS() is your goto function. (Makes more sense if you read this as NET WORKDAYS as opposed to NETWORK DAYS)
It excludes weekends plus has an optional argument that will exclude Holidays and other Non-working Days that you list in a Data Range.
NB! Just like any other Date calculations though, you need to work with genuine dates (auto-aligned to the right), otherwise this will simply error. The default weekend for the NETWORKDAYS() Function is Saturday and Sunday. If you work Saturdays or have a completely different Weekend, then use NETWORKDAYS.INTL() which has an additional argument that enables you to set your weekend day(s).