Choose dates
Select both dates from the calendar or type them directly.
- Calendar period (ISO 8601)
- Whole weeks / remaining days
Advanced date and time calculationsElapsed time with zones, clock differences, averages, sorting and interval splitting.
Details of the first result
Dates & time
How it works
A date difference can mean calendar days or an elapsed duration. March 9 noon to March 10 noon in New York in 2024 spans one calendar day but only 23 hours because daylight saving time starts.
What you can do
Count calendar days, include the end date, or measure actual elapsed time across time zones.
How to use it
- Select calendar days, elapsed time with zones, or clock-time difference. Enter the start and end in the displayed format. Use the inclusive option only for calendar days; in elapsed mode set both time zones.
- Compare adjacent lines; --- separates groups. Use one precision per group: integers, YYYY-MM, YYYY-MM-DD or local date-times. Absolute ISO durations; no zones.
- Check the result and its notes. Copy or download only after calculating; any edit clears the old result.
Errors and limits
Reversed intervals stay negative. Inclusive counting adds one in the interval’s direction, including one day for equal dates. Calendar period and week remainder describe the exclusive interval. Clock-only overnight mode assumes a fixed 24-hour day. No holiday calendar is applied.
All input stays in this tab. TXT files must be UTF-8; bulk input is limited to 200,000 characters and 10,000 lines.
Compare adjacent lines; --- separates groups. Use one precision per group: integers, YYYY-MM, YYYY-MM-DD or local date-times. Absolute ISO durations; no zones.
Extensions: year searches ≤500years; date patterns ≤200,000days; clock patterns ≤24hours; result ≤10,000rows. Magic digits mean all equal or ascending with9→0 wrap. Choose the digit representation explicitly. Rounding ties choose the later boundary; ISO weeks start Monday. Date templates: [YYYY] [MM] [DD] [DDD] [W] [E]; clocks: [HH] [hh] [mm] [ss] [A]. Natural-language output uses your interface language. Gregorian Easter:1583–4099. Interval input: start / end.
Frequently asked questions
Does the day count include both dates?
By default it measures the distance between dates: Feb28 to Mar1 in 2024 is 2 days. Including the end date makes it 3. The ISO calendar period remains P2D, so it is not confused with an inclusive count.
Are my dates uploaded or saved?
No. These calculations run in your browser. Inputs are not added to the address, stored between visits or sent to a server. Copy and download save only when you ask.