Date & time
Find the tool you need, then open it to get started.
All date & time
Add days
Add/subtract calendar days and expose timezone/calendar assumptions.
Age calculator
Calendar age and next birthday.
Business days
Custom weekends first.
Date difference
Inclusive/exclusive counting, leap years, calendar dates versus elapsed time.
Stopwatch
Measure elapsed time and take lap readings.
Time calculator
Add/subtract hours/minutes/seconds and convert decimal hours.
Time card calculator
Daily intervals, breaks and totals.
Time duration
Start/end times, crossing midnight, breaks, decimal hours and explicit timezone handling.
Time zone converter
IANA zones, date selection and DST ambiguity.
Timer
Set a countdown in seconds.
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Make dates, units and time zones explicit
Date calculations can depend on calendar rules, time zones and whether endpoints are included. A duration in hours is different from a number of calendar days when daylight-saving changes occur.
How to choose your next step
Choose the intended time zone and verify whether the start or end date counts. For working-day calculations, check which holidays and weekends apply.
Common questions about date & time
Are all days exactly 24 hours long?
Elapsed time across a daylight-saving transition can differ from a simple calendar-day count. Use the measure relevant to your schedule.
Why can the same timestamp show different dates?
A timestamp represents an instant, while a calendar date is interpreted in a time zone. Near midnight, the same instant can fall on different local dates.