Calculators
Date maths, durations and epochs
Five independent calculators. Everything runs locally in whole calendar days, so daylight-saving shifts never skew a result.
Duration between dates
Add or subtract from a date
Business days
Mon–Fri, inclusive of both ends
Choose an end date on or after the start date.
Week number & day facts
ISO-8601
Birthday countdown
age, days lived, next birthday
Enter a birth date in the past to see the countdown.
Unix epoch converter
UTC: —
Local: —
Seconds: —
Milliseconds: —