totaldaysinperiod

Total days in period, abbreviated as totaldaysinperiod in some contexts, is a basic metric used in calendar arithmetic to count the number of calendar days between a start date and an end date. The exact count may be defined as inclusive (counting both endpoints) or exclusive (not counting the end date), depending on the domain.

To calculate, establish the start date and the end date. If counting inclusively, totaldaysinperiod equals the number of days between the dates plus one. If counting exclusively, it equals the difference in days without adding one. Example: from 2024-01-01 to 2024-01-31 is 31 days inclusive and 30 days exclusive.

Edge considerations include leap years and time components. For date-only counting, use date values rather than timestamps. If start or end times are involved, normalize to a common time zone and take the date portion to avoid irregular day counts. DST does not change calendar days, but time-of-day calculations can affect durations.

Applications of totaldaysinperiod include scheduling, project planning, contract lengths, and billing quarters. In finance, it provides a baseline day count before applying day-count conventions such as Actual/Actual or 30/360, which modify the way days are weighted in interest or depreciation calculations. Distinguish this from working days, which exclude weekends and holidays.

See also: length of period, duration, date arithmetic, and day-count conventions.