Anno Mundi, abbreviated as AM or A.M., or Year After Creation, is a calendar era based on the biblical accounts of the creation of the world and subsequent history. Two such calendar eras have seen notable use historically:Since the Middle Ages, the Hebrew calendar has been based on rabbinic calculations of the year of creation from the Hebrew Masoretic Text of the Bible. This calendar is used within Jewish communities for religious purposes and is one of two official calendars in Israel. In the Hebrew calendar, the day begins at sunset. The calendar's epoch, corresponding to the calculated date of the world's creation, is equivalent to sunset on the Julian proleptic calendar date 6 October 3761 BCE. The new year begins at Rosh Hashanah, in Tishrei. Anno mundi 5784 began at sunset on 15 September 2023 according to the Gregorian calendar. The Byzantine calendar was used in the Eastern Roman Empire and many Christian Orthodox countries and Eastern Orthodox Churches and was based on the Septuagint text of the Bible. That calendar is similar to the Julian calendar except that its reference date is equivalent to 1 September 5509 BCE on the Julian proleptic calendar.

Common Era (CE) and Before the Common Era (BCE) are year notations for the Gregorian calendar, the world's most widely used calendar era. Common Era and Before the Common Era are alternatives to the original Anno Domini (AD) and Before Christ (BC) notations used for the same calendar era. The two notation systems are numerically equivalent: "2024 CE" and "AD 2024" each describe the current year; "400 BCE" and "400 BC" are the same year.