Time Tools
Timestamps, timezones, calendars, clocks and astronomy. All 90 tools run entirely in your browser, so your data never leaves your device.
All time tools
90 tools
Add Fuzziness to Calendar Dates
Randomly nudge calendar dates by up to a chosen number of days.
Add Fuzziness to Clock Times
Randomly nudge clock times by up to a chosen amount.
Analyze a Calendar Date
Report weekday, day-of-year, ISO week, leap year, zodiac sign, and season for a date.
Analyze a Clock Time
Break a clock time into 12-hour form, seconds since/until midnight, and hand angles.
Calculate Average Date
Average a list of calendar dates (mean Julian day, rounded).
Calculate Average Time
Average a list of clock times (mean of seconds since midnight).
Calculate Clock Hand Angle
Find the smaller angle between the hour and minute hands of a clock.
Check if a Year Is a Common Year
Tell whether each year you enter is a common (non-leap) year.
Check if a Year Is a Leap Year
Tell whether each year you enter is a leap year.
Convert 12-Hour Clock to 24-Hour Clock
Rewrite 12-hour AM/PM times in 24-hour form.
Convert 24-Hour Clock to 12-Hour Clock
Rewrite 24-hour times in familiar 12-hour AM/PM form.
Convert a Date to a Julian Day
Turn each calendar date into its astronomical Julian Day number (days since 4713 BC).
Convert a Julian Day to a Date
Turn each Julian Day number back into a Gregorian calendar date (YYYY-MM-DD).
Convert Cat's Age to Human Years
Convert a cat's age in years to equivalent human years.
Convert Days to Hours
Convert a list of day counts to hours (× 24).
Convert Dog's Age to Human Years
Convert a dog's age in years to equivalent human years.
Convert Gregorian Calendar to Julian Calendar
Restate each modern Gregorian date as the equivalent Old Style Julian calendar date.
Convert Hours to Days
Convert a list of hour counts to days (÷ 24).
Convert Human Time to Unix Time
Turn readable UTC date-times into Unix epoch timestamps (seconds since 1970).
Convert Human's Age to Cat Years
Convert a human age to the equivalent age of a cat.
Convert Human's Age to Dog Years
Convert a human age to the equivalent age of a dog.
Convert Julian Calendar to Gregorian Calendar
Restate each Old Style Julian calendar date as the equivalent modern Gregorian date.
Convert Military Time to Regular Time
Turn compact military HHMM(SS) values into HH:MM(:SS) clock times.
Convert Regular Time to Military Time
Turn HH:MM:SS clock times into compact military HHMM(SS) form.
Convert Seconds to Time
Turn a number of seconds into an HH:MM:SS clock time.
Convert Time Between Countries
Take a wall-clock date-time in one country and read it in another (representative zone).
Convert Time Between Timezones
Take a wall-clock date-time in one IANA timezone and read it in another.
Convert Time to Seconds
Turn each clock time into the total number of seconds it represents.
Convert Unix Time to Human Time
Turn Unix epoch timestamps (seconds since 1970) into readable UTC date-times.
Decrement a Calendar Date
Subtract a number of days, weeks, months or years from each calendar date.
Decrement a Clock Time
Subtract hours, minutes, and seconds from clock times (wraps before midnight).
Draw a Digital Clock
Draw an SVG seven-segment digital clock showing a given time.
Draw a Memento Mori Calendar
Draw a life-in-weeks (or months) grid, filling in the time already lived up to a chosen date.
Draw a Monthly Calendar
Draw an SVG month grid with weekday headers for a given month and year.
Draw an Analog Clock
Draw an SVG analog clock face with hour, minute, and second hands set to a given time.
Find a Specific Day
List every date that falls on a chosen weekday within a month and range of years.
Find a Zodiac Sign by Date
Look up the Western zodiac sign for each calendar date you enter.
Find Age Difference
Find the age gap between two or more birthdates in years, months, and days.
Find Common Years
List every common (non-leap) year within a range of years.
Find the Date by Day of the Year
Turn an ordinal day number (1-366) back into a calendar date for a chosen year.
Find the Difference Between Dates
Count the days between two calendar dates on each line (also shown broken down into years, months and days).
Find the Day of the Week
Name the weekday for each calendar date you paste in.
Find the Day of the Year
Find the ordinal day number (1-366) within the year for each calendar date.
Find Easter Dates
Compute the date of Easter Sunday for each year in a range (Gregorian Computus).
Find Friday the 13th
List every Friday that lands on the 13th within a range of years.
Find July the 4th
Show US Independence Day (July 4) and its weekday for each year in a range.
Find Leap Years
List every leap year within a range of years.
Find Season by Date
Find the season for a calendar date in either hemisphere.
Find Seconds Since Midnight
Count how many seconds have elapsed since midnight for each time.
Find Seconds Till Midnight
Count how many seconds remain until the next midnight for each time.
Find the Christmas Day
Show Christmas Day (December 25) and its weekday for each year.
Find the New Year's Day
Show New Year's Day (January 1) and its weekday for each year.
Find the Thanksgiving Day
Show US Thanksgiving (the fourth Thursday of November) for each year in a range.
Find Time Difference
Find the gap between two clock times as a duration and in seconds.
Find the Week of the Year
Find the ISO-8601 week number (weeks start Monday) for each calendar date.
Format a Calendar Date
Reformat each calendar date using tokens like YYYY, MM, DD, MMMM and dddd.
Format a Clock Time
Reformat clock times into a preset or custom pattern.
Generate a Date Sequence
Step a calendar date up or down by days, months or years.
Generate a Time Sequence
Step a clock time up or down by seconds, minutes or hours.
Generate a Unix Time Sequence
Step a Unix epoch timestamp by a fixed number of seconds.
Generate Custom Clock Times
Build clock times from a start time, a step and a count.
Generate Custom Dates
Build calendar dates from a start date, a day step and a count.
Generate Magic Calendar Dates
List neat dates where the month equals the day, like 2012-12-12.
Generate Magic Clock Times
List neat clock times with consecutive hour, minute and second.
Generate Palindromic Calendar Dates
List dates whose YYYYMMDD digits read the same forwards and back.
Generate Palindromic Clock Times
List clock times whose digits read the same forwards and backwards.
Generate Random Clock Times
Create a list of random wall-clock times of day.
Generate Random Dates
Create a list of random calendar dates within a year range.
Generate Random Unix Time
Create random Unix epoch timestamps within a range.
Increment a Calendar Date
Add a number of days, weeks, months or years to each calendar date.
Increment a Clock Time
Add hours, minutes, and seconds to clock times (wraps past midnight).
Mirror a Clock Time
Show the time an analog clock displays when seen in a mirror.
Print Dates of All Zodiac Signs
List all 12 Western zodiac signs together with their date ranges.
Round a Calendar Date
Snap each date to the nearest start of month or start of year.
Round a Clock Time
Round clock times to the nearest minute or hour, up or down.
Set Clock Hand Angle
List every 12-hour clock time whose hour and minute hands make a given angle.
Sort Calendar Dates
Sort a list of calendar dates into chronological order.
Sort Clock Times
Sort a list of clock times into chronological order.
Sort Date Intervals
Sort calendar-date ranges by their start or by their length.
Sort Time Intervals
Sort clock-time intervals by their start or by their length.
Spell a Calendar Date
Write out calendar dates in plain English words.
Spell a Clock Time
Write out clock times in plain English words.
Split Date into Intervals
Divide a date range into equal calendar sub-intervals.
Split Time into Intervals
Divide a time span into equal clock-time sub-intervals.
Truncate a Calendar Date
Drop the day (or the day and month) to snap each date down to its month or year.
Truncate a Clock Time
Drop the seconds and/or minutes from each clock time.
Validate a Calendar Date
Check whether each line is a valid calendar date.
Validate a Clock Time
Check whether each line is a valid clock time.
Visualize Date Intervals
Turn lines like '2026-01-01 to 2026-03-15 Project' into an SVG timeline of date bars.
Visualize Time Intervals
Turn lines like '09:00-10:30 Meeting' into a horizontal SVG timeline of bars.