InterCal 2.2 for Mac was free to download from our application library. The software is included in Productivity Tools. This free software for Mac OS X was originally created by Denis A. Elliott. Our built-in antivirus checked this Mac download and rated it as virus free.
From the developer:
InterCal is a date conversion program and perpetual calendar. It is not a personal appointment calendar.
The program displays calendars, one month at a time, for any month of any year in any of nine implemented calendar systems. For each day, the corresponding date in any other system can be shown˜thus an entire month is converted at once.
You may want to check out more software for Mac, such as Chronos or iCal Reply Checker, which might be similar to InterCal.