Date and Time Calculators

Timestamps, timezones, age, durations, business days and countdowns.

Convertto converts Unix timestamps and ISO dates, translates times between any two timezones with DST handling, and calculates age, date differences, business days, week numbers and countdowns. All calculations use the browser's built-in Intl and timezone database.

17 tools in this category

Age CalculatorWork out exact age in years, months and days — plus total days and the next birthday.

Meeting Agenda TimerTurn an agenda into a timed schedule with start and end times for every item.

Countdown CalculatorCount down to any date and see the gap in years, months, weeks, days, hours and minutes.

Add or Subtract Days from a DateFind the date a set number of days, weeks, months or years before or after another.

Date Difference CalculatorCount the days, weeks, months and working days between two dates.

Date Format ConverterReformat a list of dates into ISO, US, European, RFC or any custom pattern.

Day of Year CalculatorFind the ordinal day number, week number, quarter and how much of the year has elapsed.

Time Duration CalculatorAdd, subtract and average durations written as 1h 30m, 90:00 or 1:30:00.

Leap Year CheckerCheck whether a year is a leap year and see the next and previous ones, with the rule explained.

Moon Phase CalculatorFind the moon phase, illumination and age for any date, plus the upcoming new and full moons.

Sunrise & Sunset CalculatorCalculate sunrise, sunset, twilight and day length for any latitude and longitude.

Timesheet CalculatorTotal daily clock-in and clock-out times, with breaks, rounding and optional pay.

Unix Timestamp ConverterConvert Unix timestamps to human dates and back, in seconds or milliseconds.

Time Zone ConverterConvert a time between any two time zones, with daylight saving handled correctly.

Timezone Meeting PlannerFind the hours that are inside working time for everyone, across up to a dozen timezones.

ISO Week Number CalculatorFind the ISO 8601 week number, quarter and day of year for any date.

Working Days CalculatorCount business days between two dates, excluding weekends and your own holiday list.

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