Date calculator
Calculate date differences, weekdays and ISO week numbers, or add and subtract days, weeks, months and years.
Your result
Your result will appear here.
Count calendar days, without time-zone surprises.
By default, the count excludes the earlier date and includes the later one. January 1 to January 8 is 7 days. Select Include both dates to count 8 days instead.
How are calendar months counted?
Whole months keep the starting day where possible. At a shorter month’s end, the last day is used: January 31 to February 28 is one month in a non-leap year. Remaining days are shown separately. Include both dates adds one day to the span.
Are holidays excluded from weekdays?
No. Weekdays means Monday through Friday only. Public holidays and regional work schedules are not included.
What if the end date is earlier?
The tool counts the gap between the earlier and later dates and tells you when the end date comes first. Leap days are counted; daylight-saving changes do not alter a calendar-day count.
What does the ISO week number mean?
Weeks start on Monday. Week 1 contains the first Thursday of the year. Near New Year, the week-year can differ from the calendar year: January 1, 2021 belongs to week 53 of 2020.
What happens when adding months or years?
The same day is kept where possible. January 31 plus one month becomes February 28, or February 29 in a leap year. February 29 plus one year becomes February 28. Adding a week always means seven calendar days, including weekends.