Count calendar days in a span and break them into weekdays and weekend days.
Complete weeks always contain exactly two weekend days; only the leftover days depend on which weekday the span starts. Whether both endpoints count changes the total by one, which matters for notice periods. Off-by-one errors in date spans are almost always about inclusive versus exclusive endpoints rather than the arithmetic itself.
Calendar Days
Calendar days = day number difference, plus one when both endpoints count
Calendar days = day number difference, plus one when both endpoints count Complete weeks always contain exactly two weekend days; only the leftover days depend on which weekday the span starts. Whether both endpoints count changes the total by one, which matters for notice periods.
Off-by-one errors in date spans are almost always about inclusive versus exclusive endpoints rather than the arithmetic itself.
This calculator takes 7 inputs: Start date year, Start date month, Start date day, End date year, End date month, End date day, Include both end dates. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.