Date & Time Calculators

Run a live days, hours, minutes, and seconds countdown to or from an event.

Calculate the calendar time between two dates in years, months, weeks, and days.

Find the weekday for any valid calendar date.

Move a date-time forward or backward by years, months, weeks, days, hours, minutes, or seconds.

Count working days between dates with inclusive options, custom weekends, and holidays.

Calculate age on today’s date or another selected date with calendar-accurate years, months, and days.

Find a date’s ISO week number, ISO week-year, week start, and week end.

Find exact elapsed days, hours, minutes, and seconds between two date-times.

Calculate the time between two clock times, including periods that cross midnight.

Convert a date and time between IANA time zones with daylight-saving changes applied.

Convert seconds, minutes, hours, days, weeks, months, and years using clearly stated assumptions.

Convert decimal hours to hours and minutes or convert clock-style hours and minutes to decimal time.

Convert Unix seconds or milliseconds to readable date-time values and convert date-times back to Unix time.

Measure elapsed time and record individual lap results.

Alternate work, rest, and repeat rounds.

Set a labeled one-time alarm in your browser.

Display the current time in a large 12- or 24-hour format.

Keep a steady, adjustable musical tempo.