Date & Time Tools
Convert time zones, calculate dates and measure time durations in your browser.
Time Zone Converter
Convert a date and time between major world time zones with daylight-saving adjustments.
UTC Converter
Convert a UTC date and time to your chosen local time zone instantly.
World Clock
See the current time and date across major cities and time zones at a glance.
Week Number Calculator
Find the ISO week number and week-numbering year for any date.
Day of Year Calculator
Find a date's ordinal day number and the days remaining in its year.
Leap Year Checker
Check whether any year is a leap year and contains 366 days.
Countdown Timer
Count down live to a future date and time in days, hours, minutes and seconds.
Add or Subtract Days Calculator
Add or subtract any whole number of days from a calendar date.
Add or Subtract Time Calculator
Add or subtract hours and minutes from a date and time.
Business Hours Calculator
Calculate working hours between two dates while excluding weekends and time outside office hours.
Time Duration Calculator
Calculate the exact duration between two times, including overnight ranges.
What this category covers
Date and time calculations for scheduling and time-zone coordination — time zone and UTC conversion, a world clock, date arithmetic (adding or subtracting days or time), business-hours and duration calculations, and calendar facts like week numbers and leap years.
How to choose the right tool
Coordinating a meeting across regions uses Time Zone Converter or World Clock to see several zones at once; UTC Converter is for logs and systems that store timestamps in UTC. Date math splits by what's being added or subtracted: Add or Subtract Days Calculator for whole days, Add or Subtract Time Calculator for hours and minutes, and Time Duration Calculator for the elapsed time between two points. Business Hours Calculator accounts for working hours only, skipping evenings and weekends — useful for support SLAs. Calendar lookups (Week Number Calculator, Day of Year Calculator, Leap Year Checker) answer one-off scheduling questions. Countdown Timer runs a live countdown to a specific moment.
Common use cases
A remote team schedules a meeting across three time zones using World Clock; a support team calculates whether a ticket is still within its SLA using Business Hours Calculator; a developer converts a UTC log timestamp to their local time zone; an event organizer runs a countdown timer to a launch date.