June Calends
Throughout history, civilizations have developed different systems to measure and record time. From the ancient Egyptians who watched for the heliacal rising of Sirius, to the Roman reform of Julius Caesar, to the precise calculations of Omar Khayyam's Jalali calendar. Each system reflects the culture, astronomy, and needs of the people who created it.
Here you will learn about the most important calendar systems in human history, how they work, when they were created, and how they relate to each other.
You can also convert any date between 12 different calendar systems instantly, with additional information like Julian Day number, moon phase, and day of the week.
The calendar systems
The articles cover these calendar systems, presented roughly in chronological order of their origin:
- Types of Calendars — An overview of lunar, solar, and lunisolar calendar systems, plus a reference table of era abbreviations.
- Ancient Egyptian — The Sirius-based calendar with 12 months of 30 days, one of the oldest known calendar systems.
- Coptic & Ethiopian — Direct descendants of the Egyptian calendar with added leap years, still in use today.
- Julian — Caesar's reform of the Roman calendar, introduced in 46 BCE and used for over 1600 years.
- Byzantine — The Julian calendar with years counted from the Creation of the World (5509 BCE).
- Gregorian — The calendar used worldwide today, Pope Gregory XIII's correction to the Julian calendar (1582).
- Hebrew — A lunisolar calendar with a 19-year cycle, used to determine Jewish holidays.
- Islamic — A purely lunar calendar (Hijri) where months shift through the seasons.
- Persian — From Omar Khayyam's 33-year cycle to the modern Iranian Solar Hijri calendar, one of the most accurate ever devised.
- Slavic-Aryan — An ancient solar calendar with 9 months, 16-year cycles, and a 9-day week.
- Indian National — The official civil calendar of India, based on the Saka era.
- Julian Day — Not a calendar per se, but a continuous day count used in astronomy and historical chronology.
Make a printable calendar
If you need a physical calendar, Custom Calendar Maker lets you create fully customized calendars: choose the layout, add your own photos and print it at home. It works entirely in your browser with no sign-up required.