Date & Time Tools
Age, date-difference, countdown, working-days and timestamp tools for everyday planning.
free tools · no sign-up · works in your browser
Sleep Calculator
Find the best time to go to bed based on 90-minute sleep cycles, so you wake up refreshed instead of groggy.
Business Days Calculator
Count the working days (excluding weekends) between two dates — useful for SLAs, delivery and project planning.
Age Calculator
Calculate your exact age in years, months and days from your date of birth — plus total months, weeks and days lived.
Time Zone Converter
Convert any date and time between world time zones — with a live table of major cities.
Add or Subtract Days Calculator
Add or subtract days, weeks, months or years from any date to find the resulting date.
Day of the Week Calculator
Find out which day of the week any date falls (or fell) on — past or future.
Week Number Calculator
Find the ISO week number for any date, and see which dates a given week covers.
Days Until Date Calculator
Count down the days, hours and minutes until a future date or event.
Date Difference Calculator
Find the number of days, weeks, months and years between two dates, with an option to include or exclude the end date.
Which date and time tool to use
Most date questions are one of three: how long is it between two dates, what date falls a set time from now, or what a date or time is called somewhere else.
Measuring a span
Age Calculator gives an exact age in years, months and days from a date of birth. Date Difference Calculator does the same for any two dates and lets you include or exclude the end date, which changes the count by one, so decide which your contract or booking means. Business Days Calculator counts working days between two dates. It skips Saturdays and Sundays but not public holidays, so subtract those yourself for deadlines and notice periods.
Moving forward or back
Add or Subtract Days Calculator finds the date a set number of days, weeks, months or years away, such as the end of a return window or a probation period. Days Until Date Calculator counts down to an event in days, hours and minutes.
Calendars and clocks
Week Number Calculator uses ISO weeks, which run Monday to Sunday with week 1 being the first week that contains a Thursday, so a date in late December can belong to week 1 of the next year. Time Zone Converter turns a time in one zone into another, which helps when booking calls across countries. Sleep Calculator works back from your wake-up time in whole sleep cycles.
All of these run in your browser and use your device's clock and calendar.