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 written date needs a format to remove ambiguity. 03/04/2024 means March4 in US order or April3 in day-first order. ISO dates YYYY-MM-DD avoid that ambiguity.
What you can do
Convert and validate explicit date or clock formats, sort a batch, and inspect calendar facts.
How to use it
- Choose the exact input format and an output format. Paste one value per line, then convert, validate, or sort. For zoned ISO input, choose the zone used for the date and clock display. The first result shows weekday, ordinal day and ISO week.
- Check the result and its notes. Copy or download only after calculating; any edit clears the old result.
Errors and limits
No automatic locale guessing. Use four-digit years. Clock-only input cannot produce a date. ISO UTC output requires a date and time. Military HHmm output deliberately omits seconds. Sorting ISO inputs orders instants, not displayed local strings.
All input stays in this tab. TXT files must be UTF-8; bulk input is limited to 200,000 characters and 10,000 lines.
Analysis uses strict civil dates/clocks and fixed 24-hour days. Year remaining ends at next January 1; Unix values assume UTC. Calendar months and years are not fixed-duration units.
Words label each component in the interface language. They are cardinal component readings, not grammatical sentences; fractional digits are spoken separately.
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.
JD starts at noon; MJD = JD − 2400000.5. Proleptic calendars, January1 year boundary, CE1–9999; no historical adoption or time-scale correction. JD output uses floating point; inverse output rounds to seconds.
Conventional tropical zodiac date ranges; boundary dates vary across traditions. These labels do not predict personality or events.
Meteorological three-month seasons; Southern Hemisphere shifts six months. Astronomical equinoxes are not calculated.
Frequently asked questions
Can this turn 2 February into a different date by mistake?
Dates are parsed strictly in the format you select. Feb30 is rejected, with a line number in a batch, rather than being rolled into March. Changing any input disables the old copy and download results until you calculate again.
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.