📅 Date & Time
Date math, timezones and countdowns.
- Date Difference Calculator
Calculate the number of days, weeks, months and years between two dates.
- Age Calculator
Find your exact age in years, months and days from your date of birth.
- Date Format Converter
Convert a Unix timestamp or date string into every common format at once — Unix seconds/milliseconds, ISO 8601, UTC and local time.
- Business Days Calculator
Count the working days (Monday to Friday) between two dates.
- Countdown Timer
Count down live to any future date and time.
- Duration Calculator
Calculate the exact elapsed time between two dates and times, down to the second.
- Leap Year Checker
Check whether any year is a leap year, using the exact Gregorian calendar rule.
- Week Number Calculator
Find a date's ISO 8601 week number.
- Day of Year Calculator
Find a date's ordinal day number within its year (1–365 or 366).
- Timezone Converter
See what time it is in another timezone for any date and time you pick.