Notice: As an Amazon Associate, the author of this website earns from qualifying purchases.

You are at the section Calendar History

Leap Year Day Comparisons

These are the comparisons on where the leap year days were placed on the calendars using the Kalends method of counting down, and the Countup method of sequential numbering of the days of the month. We also compare the Julian to the Gregorian calendars using both the Kalends and Countup day numbering methods using the modern names of the months. Although I'm not sure if the Gregorian calendar with the Kalends version is in use anywhere in the world, I'll use it for comparing between the four calendars.

I'll begin the comparisons with the year A.D. 8 or 8 C.E. Also note where the leap year days were placed on the Countup and Kalends versions of the calendars. On the Kalends versions, the leap year day was the equivalent of February 24, but on the Countup versions, it may look like February 29 is the leap year day, but by tradition February 24 would be the real leap year day when February is 29 days long.

The leap year days are in orange.

Gregorian CountupGregorian KalendsJulian CountupJulian Kalends
Mar 02, 0008a.d. VI Non.Mar 04, 0008a.d. IV Non.
Mar 01, 0008Kal.Mar 03, 0008a.d. V Non.
Feb 29, 0008Prid. Kal.Mar 02, 0008a.d. VI Non.
Feb 28, 0008a.d. III Kal.Mar 01, 0008Kal.
Feb 27, 0008a.d. IV Kal.Feb 29, 0008Prid. Kal.
Feb 26, 0008a.d. V Kal.Feb 28, 0008a.d. III Kal.
Feb 25, 0008a.d. VI Kal.Feb 27, 0008a.d. IV Kal.
Feb 24, 0008a.d. bis. VI Kal.Feb 26, 0008a.d. V Kal.
Feb 23, 0008a.d. VII Kal.Feb 25, 0008a.d. VI Kal.
Feb 22, 0008a.d. VIII Kal.Feb 24, 0008a.d. bis. VI Kal.
Feb 21, 0008a.d. IX Kal.Feb 23, 0008a.d. VII Kal.
Feb 20, 0008a.d. X Kal.Feb 22, 0008a.d. VIII Kal.

For the year A.D. 100 or 100 C.E., the Gregorian calendar skipped a leap year day (no leap year days on years that are divisible by 100 but not by 400) so that it would be behind the Julian calendar by one day. On the Kalends version of the Gregorian calendar, it would skip bis. VI Kal., and on the Countup version, it would skip 29.

Gregorian CountupGregorian KalendsJulian CountupJulian Kalends
Mar 03, 0100a.d. V Non.Mar 04, 0100a.d. IV Non.
Mar 02, 0100a.d. VI Non.Mar 03, 0100a.d. V Non.
Mar 01, 0100Kal.Mar 02, 0100a.d. VI Non.
Feb 29, 0100 skipped
Feb 28, 0100Prid. Kal.Mar 01, 0100Kal.
Feb 27, 0100a.d. III Kal.Feb 29, 0100Prid. Kal.
Feb 26, 0100a.d. IV Kal.Feb 28, 0100a.d. III Kal.
Feb 25, 0100a.d. V Kal.Feb 27, 0100a.d. IV Kal.
Feb 24, 0100a.d. VI Kal.Feb 26, 0100a.d. V Kal.
a.d. bis. VI Kal. skipped
Feb 23, 0100a.d. VII Kal.Feb 25, 0100a.d. VI Kal.
Feb 22, 0100a.d. VIII Kal.Feb 24, 0100a.d. bis. VI Kal.
Feb 21, 0100a.d. IX Kal.Feb 23, 0100a.d. VII Kal.
Feb 20, 0100a.d. X Kal.Feb 22, 0100a.d. VIII Kal.

For the year A.D. 200 or 200 C.E., the Gregorian calendar skipped Feb 29 on the Countup version (bis. VI Kal. on the Kalends version) so that it would line up with the Julian calendar for 100 years. The date range between the two versions vary. For the Countup versions, the date range for both calendars lining up are March 1, A.D. 200 through February 28, A.D. 300. For the Kalends versions, the date range would be a.d. VI Kal. Mart. A.D. 200 through VII Kal. Mart. A.D. 300.

Gregorian CountupGregorian KalendsJulian CountupJulian Kalends
Mar 04, 0200a.d. IV Non.Mar 04, 0200a.d. IV Non.
Mar 03, 0200a.d. V Non.Mar 03, 0200a.d. V Non.
Mar 02, 0200a.d. VI Non.Mar 02, 0200a.d. VI Non.
Mar 01, 0200Kal.Mar 01, 0200Kal.
Feb 29, 0200 skipped
Feb 28, 0200Prid. Kal.Feb 29, 0200Prid. Kal.
Feb 27, 0200a.d. III Kal.Feb 28, 0200a.d. III Kal.
Feb 26, 0200a.d. IV Kal.Feb 27, 0200a.d. IV Kal.
Feb 25, 0200a.d. V Kal.Feb 26, 0200a.d. V Kal.
Feb 24, 0200a.d. VI Kal.Feb 25, 0200a.d. VI Kal.
a.d. bis. VI Kal. skipped
Feb 23, 0200a.d. VII Kal.Feb 24, 0200a.d. bis. VI Kal.
Feb 22, 0200a.d. VIII Kal.Feb 23, 0200a.d. VII Kal.
Feb 21, 0200a.d. IX Kal.Feb 22, 0200a.d. VIII Kal.
Feb 20, 0200a.d. X Kal.Feb 21, 0200a.d. IX Kal.

Here's what the days going through leap year day A.D. 300 looked like between the two calendars as the Gregorian calendar would be ahead of the Julian calendar by one day as the former skips the leap year day.

Gregorian CountupGregorian KalendsJulian CountupJulian Kalends
Mar 04, 0300a.d. IV Non.Mar 03, 0300a.d. V Non.
Mar 03, 0300a.d. V Non.Mar 02, 0300a.d. VI Non.
Mar 02, 0300a.d. VI Non.Mar 01, 0300Kal.
Mar 01, 0300Kal.Feb 29, 0300Prid. Kal.
Feb 29, 0300 skipped
Feb 28, 0300Prid. Kal.Feb 28, 0300a.d. III Kal.
Feb 27, 0300a.d. III Kal.Feb 27, 0300a.d. IV Kal.
Feb 26, 0300a.d. IV Kal.Feb 26, 0300a.d. V Kal.
Feb 25, 0300a.d. V Kal.Feb 25, 0300a.d. VI Kal.
Feb 24, 0300a.d. VI Kal.Feb 24, 0300a.d. bis. VI Kal.
a.d. bis. VI Kal. skipped
Feb 23, 0300a.d. VII Kal.Feb 23, 0300a.d. VII Kal.
Feb 22, 0300a.d. VIII Kal.Feb 22, 0300a.d. VIII Kal.
Feb 21, 0300a.d. IX Kal.Feb 21, 0300a.d. IX Kal.

Calendar History Main Page Calendar 1: The Romulus Calendar I Calendar 2: The Republican Calendar I Calendar 3: The Republican Calendar II Calendar 4: The Republican Transitional Calendar Calendar 5: The Julian-Roman-Actual-1 Calendar Calendar 6: The Julian-Roman-Transitional-1 Calendar Calendar 7: The Julian-Roman-1 Calendar Calendar 8: The Julian-Kalends-1 Calendar Calendar 9: The Julian-1 Calendar Calendar 10: The Gregorian Calendar Dual Dating Date Confusion Definition of Days on the Calendars Definition of Calendars: Others Old, New and Unknown Styles Leap Year Error on the Julian-Roman-Actual-1 Calendar What Calendars Each Country Was Using Gregorian-Julian Differences By Century New Years Days Addenda Day and Year Measurements Calendar Varieties-Gregorian Calendar Varieties-Julian Calendar Varieties-Other Years Converted From Julian Period Day Lining Up Julian Dates Between Earth and Mars The Martian Calendar of Earth Converting From the Julian Period Date Creating a Julian Period Day Database File Truncating Answers Conversion Between Julian-1 and Gregorian Calendars Create a Calendar Leap Year Day Comparisons Swedish Calendar 1700-1712 Fractions of Years, Etc.
Dave's Fun Stuff's Stuff Green Concepts Jesus' Date of Conception Calendar Coincidence Calendar History Units of Time Food to Lower Blood Pressure Fun With Money Electricity Rates Optical Illusions Celebrity Autographs Eat More Potassium! TV Died State Abbreviations Volume Measurements Fun With Math Strip Unicode Mesa Silicon Cajon
Market Zone:
Amazon Shopping The DFS Market
TV Zone:
Find your favorite TV shows with "Let's Watch TV!"
Amazon Shopping Stuff! SDN Media News and More
Dave's Fun Stuff Mega Birthdays Contact Webmaster

© 1995-2021. davesfunstuff.com All Rights Reserved. Reproduction of any part of this website without expressed written consent is prohibited.

Notice Of Disclosure (updated Oct 2020):

"David Tanny, owner and operator of the domains davesfunstuff.com, dfsxradio.com, megabirthdays.com, eightisenough.com, sandiegoradionews.com and davidtanny.com, and its related subdomains, is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. By making a purchase through the links to an amazon product or group page, this webmaster earns a small commission to pay for website administration duties. Linking does not imply endorsement. Clicking does not cost the visitor money. Please read the reviews of the product and return policies before deciding on making a purchase from a seller on Amazon. You will not be required to buy what you don't want or need. Thank you readers."

Website Cookie Policy