13 Months, a Complete Ethiopian Calendar is a free Chrome add-on developed by eLexicon Tech Solutions. This Ethiopian calendar offers a wide range of features, including conversion, holiday markings, and more.

Ethiopia follows a unique calendar system, with 12 months of 30 days each and an additional 13th month of 5 days (which becomes 6 days every four years). This calendar provides users with a comprehensive set of functionalities, some of which are:

1. Marking today's date upon opening the calendar (requires correct computer date in Gregorian format).

2. Displaying both Ethiopian and Gregorian dates when hovering over each day.

3. Highlighting Ethiopian National days, Christian Holidays, and approximate Muslim Holidays starting from 1988 EC.

4. Allowing users to navigate to any specific Ethiopian day.

5. Offering conversion capabilities from Ethiopian to Gregorian dates and vice versa.

6. Providing a page dedicated to national events and holidays, with easy navigation to any specific day on the calendar.

This calendar proves to be highly useful and simplifies calendar needs for a span of 150 years, from 1900 to 2050.

Please note that any comments or feedback can be sent to the developers via email at or