What this date calculator does
The calculator has three modes: days between dates, add or subtract calendar time, and time duration between two timestamps. Use it for planning periods, event windows, deadlines, timelines, and simple elapsed-time checks.
Inclusive vs elapsed day counts
Elapsed days count the distance from one date to another. Inclusive days count both the start and end date. For example, a Monday-to-Friday work window is four elapsed days but five inclusive calendar dates.
Common questions
Does the calculator include the end date?
By default it counts the elapsed days between dates. Turn on include the end date when you want an inclusive count, such as a stay, event window, or coverage period.
What are weekdays?
Weekdays count Monday through Friday and exclude Saturday and Sunday. Public holidays are not removed because holiday calendars vary by country and region.
Which timezone does time duration use?
The timestamp mode uses your browser timezone for datetime-local inputs. The date-only modes use calendar dates and avoid time-of-day calculations.