Date & time calculators

Calendar-aware tools for ages, intervals, and milestones. Every calculation respects real month lengths and leap years, so the result matches what an institution would write — not a 30-day-month approximation.

Date arithmetic is the category where casual approximations quietly produce wrong answers. “Months between two dates” is famously ambiguous — is February 28 to March 28 one month, or should the result be 28 days? The age calculator reports both, plus exact total days and weeks, so a visa form, an HR record, and a child’s school enrolment all get the answer they actually want. The working-days tool counts Monday-to-Friday weekdays in a range — the basis for invoicing, contractor billing, and SLA windows — and surfaces the calendar-day total alongside so you can pick up the right denominator. The timezone and world-clock tools handle daylight-saving transitions automatically using the IANA timezone database, so a meeting scheduled for “next Wednesday at 09:00 New York time” lands at the correct local time in every participant’s city across the DST boundary in spring and fall. The timestamp converter accepts seconds, milliseconds, and microseconds since the Unix epoch, with an autodetect that catches the most common copy-paste mistakes.