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Calendar Date Validator

World's Simplest Time Tool

With this browser-based application, you can check if a calendar date exists and is correct. It tests if the date (and optional time) is well-formatted and also analyzes the limits of each date component. You can validate as many calendar dates as you want, choose the date status format, and print a descriptive error message. Created by computer nerds from team Browserling.

᠎᠎᠎          Tool Options

Status Message

Print a short status of
validated dates.

Detailed Message

Print a full description
of the date error.

What Is a Calendar Date Validator?

This is a quick online utility for validating calendar dates. The date validation algorithm that we implemented checks the format of a date, the components of a date, and verifies the date exists (for example, a leap year exists only once every 4 years). Once the validation is complete, it displays the result of the test on the screen. If the date is correct, the tool prints "Date is valid" (or just "Valid" if the short message form is enabled). If the date is incorrect, the tool prints "Date is invalid" (or "Invalid" in the short form). The first thing the program checks is that the date has a correct format and that all parts of the date contain only numbers. A valid full date format is "YYYY-MM-DD hh:mm:ss", however it can also be shortened to "YYYY-MM-DD hh:mm", "YYYY-MM-DD hh", "YYYY-MM-DD", "YYYY-MM", or just "YYYY". The program then checks each date component individually. The year must be at least -271821 (which is 271821 BC) and must not exceed 275760 (AC). For months, valid values are from 1 to 12. The dates in each month may differ, some months have 28 days, some 29, some 30, and some 31. The program checks the number of days in each month separately and displays an error if the number of days in that month are exceeded. If the input date has a clock time part, then it's also run through a number of checks. In particular, the maximum time is limited to 24:00:00, the minutes must not exceed 59m, and the seconds must not exceed 59s. To validate multiple calendar dates, enter them one per line into the input field. To get a shortened status check result use the "Short Status" checkbox option and to display a detailed description of the date error, use the checkbox "Show Detailed Error". Timeabulous!


Calendar Date Validator Examples

Click to try!

Validate Calendar Dates

This example verifies two calendar dates. It checks the year, month, and date of each date and prints the result to the output text area. The first date is valid but the second date is invalid because there are a maximum of 12 months in a year but the date has "13" in the month component.

2022-02-15 2022-13-15
Date is valid. Date is invalid.
Required options
These options will be used automatically if you select this example.
Print a short status of
validated dates.
Print a full description
of the date error.

Date Check with Descriptions

In this example, we enter many calendar dates as the input and quickly analyze the validity of all dates. We also activate the verbose error option so that we can instantly find and fix errors in calendar dates.

2022-02-15 12:00:00 2017-10-12 1999-00-25 16:30 2026-11-30 02:36 2030-13-16 2023-11-20 01:26 2020-1-0 13:20:40 2021-07-24 2005-04-40 2001-02-18
Date is valid. Date is valid. Date is invalid. (Month is less than 1.) Date is valid. Date is invalid. (Month is greater than 12.) Date is valid. Date is invalid. (Day is less than 1.) Date is valid. Date is invalid. (Day is greater than 31.) Date is valid.
Required options
These options will be used automatically if you select this example.
Print a short status of
validated dates.
Print a full description
of the date error.

Multi-date Verification

In this example, we catch all the incorrect dates in a long list of dates. We use the short status output format and also add a short error description in parentheses to each invalid date.

2028-07-01-2 14:28 2001-01-28 14:10 2028y-10-14 10:00 -600000-01-01 1996-01-16 3000000-09-12 2025-02-31 12:00:00 2005-07-10 00:19:45 2027-15-09 02:80:33 2005-02-16 02:40
Invalid. (Valid format YYYY-MM-DD hh:mm:ss.) Valid. Invalid. (Valid format YYYY-MM-DD hh:mm:ss.) Invalid. (Date is too small.) Valid. Invalid. (Date is too big.) Invalid. (Feb 2025 consists of 28 days.) Valid. Invalid. (Minutes greater than 59.) Valid.
Required options
These options will be used automatically if you select this example.
Print a short status of
validated dates.
Print a full description
of the date error.

Pro tips Master online time tools

You can pass input to this tool via ?input query argument and it will automatically compute output. Here's how to type it in your browser's address bar. Click to try!

https://onlinetools.com/time/validate-calendar-date?input=2022-02-15%0A2022-13-15&show-details=false&short-status=false

All Time Tools

Didn't find the tool you were looking for? Let us know what tool we are missing and we'll build it!
Quickly visualize your life in weeks or months.
Quickly draw a wall clock that shows a particular time.
Quickly draw an electronic clock that shows a particular time.
Quickly draw a monthly calendar for any month of the year.
Quickly print a list of neat-looking clock times (such as 10:11:12).
Quickly print a list of neat-looking calendar dates (such as 2055-05-05).
Quickly print a list of symmetric clock times (such as 05:22:50).
Quickly print a list of symmetric dates (such as 2020-02-02).
Quickly convert clock time in H:M:S format to seconds.
Quickly convert seconds to clock time in H:M:S format.
Quickly convert time in 24 hour format to 12 hour format.
Quickly convert time in 12 hour format to 24 hour format.
Quickly find how many seconds have passed since midnight.
Quickly find how many seconds are left till midnight.
Quickly find the difference between two clock times.
Quickly find the difference between two calendar dates.
Quickly find the age difference between two or more people.
Quickly add hours, minutes, and seconds to the given time.
Quickly subtract hours, minutes, and seconds from the given time.
Quickly add days, months, and years to the given date.
Quickly subtract days, months, and years to from the given date.
Quickly change the current time format to any new format.
Quickly change the current date format to any new format.
Quickly round the given clock time up or down.
Quickly round the given calendar date up or down.
Quickly drop seconds and minutes from a clock time.
Quickly drop days and months from a calendar date.
Quickly sort clock times in ascending or descending order.
Quickly sort calendar dates in ascending or descending order.
Quickly sort time intervals by their start time or length.
Quickly sort date intervals by their start date or length.
Quickly check if the given clock time is valid.
Quickly check if the given calendar date is valid.
Quickly find how many hours are in the given days.
Quickly find how many days are in the given hours.
Quickly find the astrological sign by the birthday or any date.
Quickly print a list of the dates of all astrological signs.
Quickly find the average value of multiple clock times.
Quickly find the average value of multiple calendar dates.
Quickly generate a list of random clock times.
Quickly generate a list of random calendar dates.
Quickly create a list of clock times that match your criteria.
Quickly generate a list of calendar dates that match your criteria.
Quickly split the given time period into multiple intervals.
Quickly split the given date period into multiple intervals.
Quickly generate increasing or decreasing clock times.
Quickly generate increasing or decreasing calendar dates.
Quickly print a list of all leap years.
Quickly print a list of all common years.
Quickly test if the given year is a leap year.
Quickly test if the given year is a common year.
Quickly find how old a cat would be if it was a human.
Quickly find how old a human would be if he/she was a cat.
Quickly find how old a dog would be if it was a human.
Quickly find how old a human would be if it was a dog.
Quickly convert a modern Gregorian date to a Julian date.
Quickly convert an ancient Julian date to a Gregorian date.
Quickly calculate the Julian day number for any calendar date.
Quickly convert the Julian day to a regular calendar date.
Quickly print a list of all Easter dates for all years.
Quickly convert a UNIX Epoch time to a human-readable time.
Quickly convert human-readable time to a UNIX Epoch time.
Quickly generate increasing or decreasing UNIX timestamps.
Quickly generate one or more random UNIX Epoch times.
Quickly convert a HH:MM:SS clock to a military HHMM clock.
Quickly convert a military clock HHMM to a HH:MM:SS clock.
Quickly write a clock time in text format (as English text).
Quickly write a calendar date in text format (as English text).
Quickly add slight perturbations to the given clock times.
Quickly add slight perturbations to the given calendar dates.
Quickly find what day of the week the given calendar date falls on.
Quickly find what day of the year the given calendar date falls on.
Quickly find what week of the year the given calendar date falls on.
Quickly calculate the calendar date from a day number of a year.
Quickly find the angle between the hour hand and minute hand.
Quickly print a list of all clock times with a specific hand angle.
Quickly print all dates when a specific day happens.
Quickly find all Fridays that fall on the 13th day of the month.
Quickly create a list of all Independence Day dates.
Quickly create a list of all Christmas Day dates.
Quickly create a list of all New Year dates.
Quickly create a list of all Thanksgiving dates.
Quickly show useful information about a particular clock time.
Quickly show useful information about a particular calendar date.
Quickly draw a timeline of multiple time intervals.
Quickly draw a visualization of multiple date intervals.
Quickly find the time a clock shows if you look at it in a mirror.
Quickly convert time and date from one timezone to another.
Quickly convert time and date from one country to another.
Quickly print the season (winter, spring, summer, autumn) by date.

Coming Soon

These time tools are on the way!
Draw a Binary Clock

Draw a binary clock that shows time in base two.

Draw a Salvador Dali Clock

Draw a clock in Salvador Dali style showing custom time.

Draw a Weird Clock

Draw a weird-looking clock that shows a particular time.

Draw a Pi Clock

Draw a π clock with π hours in a day.

Draw a 360° Clock

Draw a 360° clock with 360 degrees in a day.

Animate an Analog Clock

Create a GIF animation of an analog clock.

Animate a Digital Clock

Create a GIF animation of a digital clock.

Animate a Broken Clock

Create a GIF animation of a clock that's broken.

Draw a Daily Calendar

Draw a daily calendar for a single day.

Draw a Weekly Calendar

Draw a weekly calendar for any week of the month.

Draw a Yearly Calendar

Draw a yearly calendar for the entire year.

Draw a Lunar Calendar

Draw a calendar that shows moon phases.

Draw a Solar Calendar

Draw a calendar that shows the seasons and Sun's position.

Draw a Sunrise and Sunset Calendar

Draw a calendar that shows when the Sun rises and sets.

Draw a Moonrise and Moonset Calendar

Draw a calendar that shows when the Moon rises and sets.

Create an Animated Timer

Draw an animation that counts down (or up) time.

Animate an Hourglass

Create a GIF animation of a sand clock.

Draw an Infinite Spiral Clock

Animate a timeless clock that goes in an infinite spiral.

Draw Time as a Pie Chart

Visualize the given clock time as a pie chart.

Draw Date as a Pie Chart

Visualize the current year as a pie chart.

Draw Time as a Bar Chart

Visualize the given clock time as a bar chart.

Draw Date as a Bar Chart

Visualize the current year as a bar chart.

Draw Time as a Pixel Wall

Visualize the given clock time as a pixel wall (1px = 1sec).

Draw Date as a Pixel Wall

Visualize the current year as a pixel wall (1px = 1day).

Draw Time as Bubbles

Visualize the given clock time as bubbles.

Draw Date as Bubbles

Visualize the current year as bubbles.

Draw a Time Arrow

Visualize the given clock time as an arrow.

Convert Time to Percentage

Quickly calculate time passed and left in the current day as pct.

Convert Date to Percentage

Quickly calculate time passed and left in the current year as pct.

Convert Time to Binary Time

Convert regular clock time to binary clock time (bintime).

Convert Date to Binary Date

Quickly regular calendar date to binary date (bindate).

Convert Time to Decimal Time

Convert regular clock time to decimal clock time (dectime).

Convert Date to Decimal Date

Quickly regular calendar date to decimal date (decdate).

Convert Time to Hex Time

Convert regular clock time to hexadecimal time (hextime).

Convert Date to Hex Date

Quickly regular calendar date to hexadecimal date (hexdate).

Animate Moon's Phases

Create a GIF animation of the Moon for a particular month.

Animate Moon's Orbit

Create an animation of the Moon orbiting the Earth.

Animate Mercury's Orbit

Create a 88 day animation of the Mercury orbiting the Sun.

Animate Venus's Orbit

Create a 225 day animation of the Venus orbiting the Sun.

Animate Earth's Orbit

Create a 365 day animation of the Earth orbiting the Sun.

Animate Mars's Orbit

Create a 687 day animation of the Mars orbiting the Sun.

Animate Jupiter's Orbit

Create a 4,330 day animation of the Jupiter orbiting the Sun.

Animate Saturn's Orbit

Create a 10,756 day animation of the Saturn orbiting the Sun.

Animate Uranus's Orbit

Create a 30,687 day animation of the Uranus orbiting the Sun.

Animate Neptune's Orbit

Create a 60,190 day animation of the Neptune orbiting the Sun.

Animate Pluto's Orbit

Create a 90,560 day animation of the Pluto orbiting the Sun.

Animate Solar System

Create an animation of all planets in the Solar System.

Animate Mars's Moons

Create an animation of Phobos and Deimos orbiting Mars.

Animate Jupiter's Moons

Animate Io, Europa, Ganymede, Callisto orbiting Jupiter.

Animate Saturn's Moons

Animate Titan, Rhea, Iapetus, Enceladus orbiting Saturn.

Animate Uranus's Moons

Animate Titania, Oberon, Umbriel, Ariel, Miranda orbiting Uranus.

Animate Neptune's Moons

Animate Triton, Nereid, and Proteus orbiting Neptune.

Animate Pluto's Moons

Animate Charon, Nix, Hydra, Kerberos, Styx orbiting Pluto.

Find When Planets Align

Find dates when two or more planets align in a straight line.

Find Dates of Solar Eclipse

Find dates when the solar eclipse happens.

Find Dates of Lunar Eclipse

Find dates when the lunar eclipse happens.

Find Your Age on Other Planets

Calculate your age based on the orbital period of other planets.

Create a Time Matrix

Represent a clock time as a matrix.

Create a Date Matrix

Represent a calendar date as a matrix.

Create a Time Vector

Represent a clock time as a vector.

Create a Date Vector

Represent a calendar date as a vector.

Visualize Time Series

Draw a time series chart.

Find Overlapping Times

Given a bunch of time intervals, find overlapping intervals.

Generate Overlapping Times

Generate a bunch of overlapping time intervals.

Generate Non-overlapping Times

Generate a bunch of non-overlapping time intervals.

Generate Random Time Intervals

Generate random clock time intervals.

Find Overlapping Dates

Given a bunch of date intervals, find overlapping intervals.

Generate Overlapping Dates

Generate a bunch of overlapping date intervals.

Generate Non-overlapping Dates

Generate a bunch of non-overlapping date intervals.

Generate Random Date Intervals

Generate random calendar date intervals.

Swap Clock Hands

Swap a clock's hour hand with minute hand.

Reverse Clock Time

Find the reverse of the given clock time.

Invert Clock Time

Find the inverse of the given clock time.

Shift Clock Time

Shift the given clock time by any time interval.

Change Clock Scale

Change the clock scale from 24 hours to any other hours.

Generate Valid Clock Times

Generate a list of valid clock times (for testing).

Generate Invalid Clock Times

Generate a list of invalid clock times (for testing).

Generate Valid Calendar Dates

Generate a list of valid calendar dates (for testing).

Generate Invalid Calendar Dates

Generate a list of invalid calendar dates (for testing).

Add Errors to Clock Times

Create errors in the given clock times (for testing).

Add Errors to Calendar Dates

Create errors in the given calendar dates (for testing).

Convert Date to Seconds

Convert a calendar date to seconds.

Convert Seconds to Date

Convert seconds to a calendar date.

Convert English to Crontab

Create a crontab expression from human language.

Convert Crontab to English

Rewrite a crontab entry into human language.

Find Week of the Month

Quickly find the week of the month of a calendar date.

Find Days Since the Start of Year

Quickly find how many days have passed since start of the year.

Find Days Till the End of Year

Quickly find how many days are left till the end of the year.

Find Days Till a Specific Date

Quickly find how many days are left till a specific date.

Convert Seconds To Minutes

Find how many minutes are in the given seconds.

Convert Seconds To Hours

Find how many hours are in the given seconds.

Convert Seconds to Days

Find how many days are in the given seconds.

Convert Seconds to Weeks

Find how many weeks are in the given seconds.

Convert Seconds to Months

Find how many months are in the given seconds.

Convert Seconds to Years

Find how many years are in the given seconds.

Convert Minutes to Seconds

Find how many seconds are in the given minutes.

Convert Minutes To Hours

Find how many hours are in the given minutes.

Convert Minutes to Days

Find how many days are in the given minutes.

Convert Minutes to Weeks

Find how many weeks are in the given minutes.

Convert Minutes to Months

Find how many months are in the given minutes.

Convert Minutes to Years

Find how many years are in the given minutes.

Convert Hours To Seconds

Find how many seconds are in the given hours.

Convert Hours to Minutes

Find how many minutes are in the given hours.

Convert Hours to Weeks

Find how many weeks are in the given hours.

Convert Hours to Months

Find how many months are in the given hours.

Convert Hours to Years

Find how many years are in the given hours.

Convert Days to Seconds

Find how many seconds are in the given days.

Convert Days to Minutes

Find how many minutes are in the given days.

Convert Days to Weeks

Find how many weeks are in the given days.

Convert Days to Months

Find how many months are in the given days.

Convert Days to Years

Find how many years are in the given days.

Convert Weeks to Seconds

Find how many seconds are in the given weeks.

Convert Weeks To Minutes

Find how many minutes are in the given weeks.

Convert Weeks To Hours

Find how many hours are in the given weeks.

Convert Weeks to Days

Find how many days are in the given weeks.

Convert Weeks to Months

Find how many months are in the given weeks.

Convert Weeks to Years

Find how many years are in the given weeks.

Convert Months to Seconds

Find how many seconds are in the given months.

Convert Months To Minutes

Find how many minutes are in the given months.

Convert Months To Hours

Find how many hours are in the given months.

Convert Months to Days

Find how many days are in the given months.

Convert Months to Weeks

Find how many weeks are in the given months.

Convert Months to Years

Find how many years are in the given months.

Convert Years to Seconds

Find how many seconds are in the given years.

Convert Years To Minutes

Find how many minutes are in the given years.

Convert Years To Hours

Find how many hours are in the given years.

Convert Years to Days

Find how many days are in the given years.

Convert Years to Weeks

Find how many weeks are in the given years.

Convert Years to Months

Find how many months are in the given years.

Convert a Bird's Age to Human Years

Find how old a human would be if he/she was a bird.

Convert a Human's Age to Bird Years

Find how old a bird would be if it was a human.

Convert Earth Time to Mars Time

Convert clock time on Earth to clock time on Mars.

Convert Mars Time to Earth Time

Convert clock time on Mars to clock time on Earth.

Convert Earth Date/Time to Stardate

Convert Earth time to Star Trek's stardate.

Convert Stardate to Earth Date/Time

Convert Star Trek's stardate to Earth time.

Generate Equal H:M:S Times

Print a list of clock times with hours equal mins equal secs.

Generate Equal Y-M-D Dates

Print a list of calendar dates with years equal months equal days.

Set Straight Clock Hands

Print a list of all clock times when hands are in a straight line.

Normalize Clock Times

Given clock times in various formats, convert them to one format.

Normalize Calendar Dates

Given calendar dates in various formats, make them the same format.

Rotate Clock Times

Cyclically shift HH, MM, SS time parts to the left or right.

Rotate Calendar Dates

Cyclically shift YYYY, MM, DD date parts to the left or right.

Freeform Time Calculator

Perform freeform clock time arithmetics.

Freeform Date Calculator

Perform freeform calendar date arithmetics.

Calculate Clock Sum

Find the sum of hours plus minutes plus seconds.

Calculate Calendar Sum

Find the sum of years plus months plus days.

Find Clock Sum

Find clock hand position so that hr + min + sec equals your value.

Find Calendar Sum

Find calendar date so that year + months + day equals your value.

Generate Clock Emojis

Print all clock icons from 00:00 to 24:00.

Create Zalgo Time

Generate date and time that only Zalgo can understand.


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