by John P. Pratt
Updated 2 May 2021
Enter event names in the left-hand column, overwriting the first examples shown, if desired (perhaps to save results with a screen shot). Type the date on our modern Gregorian calendar in the next column in format shown and press Enter. Or change any column to the Julian or Old English Calendar and enter. That date will automatically be displayed on the other calendars in the other columns. At any time, if you wish to change what version of the calendar you are using (such as changing from the Pratt to the GMT version of the Mayan calendar), simply change the version at the column head and the entire column will be recalculated accordingly. You can toggle between short and long names in the Format menu. You may also change the calendar in any column to other choices, and the format of the date. If the format for other calendars shows a year, you can usually enter the date in that column and it will change all calendars to that date. You may also use the Add button to have up to a total of 16 calendars. If you wish to enter dates to quarter-day accuracy, use the "Show Accuracy" choice on the Gregorian calendar and after the date enter "am" or "pm" for morning or afternoon times, or am* for before sunrise or pm* for after sunset (when the *'s are shining). If not specified, the default time of day is afternoon. Days which are holy are shown in blue and those which are most holy in red. If you don't see the sheet at all, make sure Java is turned on and allowed to run this applet. It probably won't run on smart phones because they don't run Java.
Notice of Sun 9 Aug 2020: The Chrome browser now has an extension to run the Java applet needed for this page. Search for "Chrome browser CheerpJ extension" or go directly to chrome.google.com/webstore/detail/cheerpj-applet-runner/bbmolahhldcbngedljfadjlognfaaein to download the extension. Then go to this page and simply click on an extension icon to run this applet! It may take a minute or so to come up. On my Linux version it does not show the red and blue colors for holy days, but it correctly calculates the dates.