Date & Time

Date arithmetic, business days, timers and world clocks.

Count days between two dates; count business days, either excluding weekends or with the days off set to whichever weekdays you choose; find the date N business days out; track ages and countdowns to an anniversary; convert between Japanese era years and the Gregorian calendar; validate ISO 8601 strings; find ISO week numbers; and identify calendar quarters. On the time side there are world clocks, a cross-timezone meeting planner, daylight-saving transition dates, a stopwatch and a Pomodoro timer. The date calculations have been checked against boundary cases including leap years and leap days.