- Counts.
- Differences are calendar days, not 24-hour blocks: in a New York browser, 7–9 March 2026 still counts 2 days and the business row reads Total days (incl.) 3.
- Workdays.
- "CN statutory holidays" (with make-up workdays) is on by default; switch it off for a Monday–Friday week. Above roughly ten years the count stops: range too large.
- Calendar arithmetic.
- Years first, then months, then days: 31 January 2026 plus 1 month gives 3 March 2026, and 29 February 2024 plus 1 year gives 1 March 2025, because the target dates do not exist in those months. There is no 1582 Julian-to-Gregorian switch here: 10 October 1582 parses as an ordinary date (1582-10-10T00:00:00.000Z).
- World Clock.
- Offsets come from the browser's IANA time-zone database. A wall time inside a spring-forward gap: 01:30 on 29 March 2026 in London does not exist; the table resolves it to 01:30 UTC, so the London row reads 02:30. A fall-back time that occurs twice resolves to the later, standard-time instance.
- Timestamps.
- Numeric input is read by digit count: 10 digits as seconds, 13 as milliseconds, 16 as microseconds. A date-only string is taken as UTC midnight: 2026-01-01 shows Local 08:00:00 in UTC+8.
- One date or number at a time.
- The fields do not parse a formula; for arithmetic on the figures a date produces, use the standard calculator.