Elapsed days, calendar days, and inclusive dates
Many date disputes are counting-convention disputes. A clear label prevents a correct calculation from being misunderstood.
Define whether the start date is counted.…
Define whether the start date is counted. A duration from Monday to Tuesday is one elapsed calendar-day boundary, while an inclusive schedule may describe two dates.
Use a time-zone-aware method when the requirement…
Use a time-zone-aware method when the requirement is hours or minutes. Date-only fields should not be presented as exact elapsed time.
Document weekends, holidays, and daylight-saving behavior when…
Document weekends, holidays, and daylight-saving behavior when a date difference controls billing, delivery, age, or compliance.
Use the related tool carefully
This guide is paired with a browser-only utility. The tool is a practical aid for small examples and inspection; it is not a substitute for application testing, a formal data pipeline, or professional review where the decision has higher consequences.
Open the related Date Difference Calculator