# Julian to Gregorian Calculator

## World's Simplest Time Tool

With this browser-based application, you can convert any date from the ancient Julian calendar to the modern Gregorian calendar that we use today. You can paste several Julian dates into the input and calculate the corresponding Gregorian calendar dates in the output. If you enter several Julian dates (one per line), you can instantly see the difference in days between both calendars. Additionally, you can change the Gregorian calendar date format in the options. Created by computer nerds from team Browserling.

Tool Options

#### Gregorian Date Format

Choose the output Gregorian
date format.
Create a custom date format
using abbreviations. (Activated
by selecting custom mode).

#### Custom Date Format Cheat Sheet

If you selected the "custom" date
format in the previous option,
then here's a cheat sheet for

• YYYY/YY – year,
• MMMM/MMM/MM – month,
• dddd/ddd – day of week,
• DD – day,
• hh – hour,
• mm – minute,
• ss – second.

in the output Gregorian dates.
Use 12-hour time parts in the
output Gregorian dates.

## What Is a Julian to Gregorian Calculator?

This is a quick online utility for calculating the Gregorian calendar date from the given Julian calendar date. The Julian calendar was introduced on January 1, 45 BC by Julius Caesar. In this calendar, the length of the year was 365¼ days, which means every four years the extra quarter of the day formed an additional day. A year with this extra day, by the way, is called a leap year. In 1582, the Julian calendar was replaced by the Gregorian calendar, which is the modern calendar that we use today. The Gregorian calendar is astronomically more accurate and the year lasts 365.2425 days. In the Gregorian calendar, years that are divisible by 4 are considered leap years, with the exception of years that are divisible by 100 and not divisible by 400. For example, the years 2100, 2200, 2300, and 2400 in the Gregorian calendar have 365, 365, 365, and 366 days (only the year 2400 is a leap year with an extra calendar day), however, in the Julian calendar, they have 366, 366, 366, and 366 days (there are 4 extra calendar days). It means that for every 400 years, the Gregorian calendar drifts ahead of the Julian calendar by 3 days. This is also the key reason why the Julian calendar was replaced by the Gregorian version. In this program, we implemented a precise mathematical algorithm that converts any date from one calendar standard to the other. Once you enter a Julian date in the format "YYYY-MM-DD" in the input, you'll get a Gregorian date in the output. Our tool can also convert multiple dates at once if you enter them in a column, one after another on separate lines. You can choose the Gregorian date format for the output by selecting a format from the list in the options or by creating a custom date format from a template using date component abbreviations (see the abbreviations cheat sheet in the options). You can also add or remove date padding (so that all date components are 2 or 4 digits long) and turn the time part into a 12-hour or 24-hour clock format. If you need to perform the reverse operation and convert a modern Gregorian date to the older Julian calendar, you can use our Gregorian to Julian Date Calculator utility. Timeabulous!

## Julian to Gregorian Calculator Examples

Click to try!

### Wikipedia Launch Date

This example takes a Julian calendar date 2001-01-02 as the input and converts it to a Gregorian calendar date. In the output, we get 2001-01-15 and it's an important date, as on this day, Wikipedia was created. As you can see, the difference between both calendar dates is 13 days. In fact, all dates from Feb 29, 1900 to Feb 28, 2100 of the Julian calendar (which correspond to the dates from Mar 13, 1900 to Mar 13, 2100 of the Gregorian calendar) have a difference of 13 days as compared to the Gregorian calendar.

2001-01-02
2001-01-15
Required options
These options will be used automatically if you select this example.
Choose the output Gregorian
date format.
Create a custom date format
using abbreviations. (Activated
by selecting custom mode).
in the output Gregorian dates.
Use 12-hour time parts in the
output Gregorian dates.

### Reform by Pope Gregory XIII

In this example, we go back in time when the transition from the Julian calendar to the Gregorian calendar was announced. The reform in the 16h century by Pope Gregory XIII shifted the calendar by 10 days. Namely, Thursday, October 4, 1582 (still in the Julian calendar) was followed by Friday, October 15, 1582 (now the Gregorian calendar) and October 5 to October 14 were skipped. In the output, we print the Gregorian date for the day that follows the final Julian calendar day in a custom format, and we also include the day of the week.

1582-10-05
Fri, October 15, 1582
Required options
These options will be used automatically if you select this example.
Choose the output Gregorian
date format.
Create a custom date format
using abbreviations. (Activated
by selecting custom mode).
in the output Gregorian dates.
Use 12-hour time parts in the
output Gregorian dates.

### Difference in Days Between Calendars

In the input of this example, we enter multiple Julian calendar dates that are all 400 years apart. We start the dates at "400-01-01 06:00:00" and end the list with the date "2400-01-01 00:00:00". The output shows that the difference in the number of days between both calendars grows as the years increase. To be precise, every 400 years the difference between the Julian and Gregorian calendars increases by 3 days. In the output, we remove the padding and display the clock time (which doesn't change between calendars) in a 12-hour format.

400-01-01 06:00:00 800-01-01 00:00:00 1200-01-01 18:00:00 1600-01-01 12:00:00 2000-01-01 06:00:00 2400-01-01 00:00:00
400-1-2 6:0:0 am 800-1-5 0:0:0 am 1200-1-8 6:0:0 pm 1600-1-11 12:0:0 pm 2000-1-14 6:0:0 am 2400-1-17 0:0:0 am
Required options
These options will be used automatically if you select this example.
Choose the output Gregorian
date format.
Create a custom date format
using abbreviations. (Activated
by selecting custom mode).
in the output Gregorian dates.
Use 12-hour time parts in the
output Gregorian dates.

### Pro tipsMaster 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!

### All Time Tools

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.
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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 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).

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

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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