Aeons to Months (Gyr to mo)

1 aeon equals 12,000,000,000 months exactly.

1 aeon = 12,000,000,000 months

How to convert aeons to months

To convert aeons to months, multiply the number of aeons by 12,000,000,000. This factor is exact. To go the other way, multiply months by 8.333333333×10⁻¹¹ (rounded).

months = aeons × 12,000,000,000

Example: 10 aeons = 120,000,000,000 months.

Months and years are not constant. This site uses the average Gregorian year of 365.2425 days, so one 'year' converts to 365.2425 days, not 365; use 'common year' for exactly 365 days.

About these units

Aeon (Gyr)

AstronomicalCurrent unit

One billion years. The Earth is about 4.5 aeons old.

Aeon comes from a Greek word meaning life, vital force, or an age, and its Latin cousin aevum lies behind English words such as eternal and medieval. In ordinary speech it means any very long, indefinite stretch. Philosophical and religious traditions use it differently, with Buddhist and Hindu texts sometimes rendering kalpa as aeon and Gnostic writers using it for divine emanations.

Astronomers fix a definite size, defining an aeon as a billion years. The figure used here is therefore 10 to the power of 9 Gregorian years, about 3.16 times 10 to the power of 16 seconds, which is a convention rather than a measured length. Geologists use the closely related spelling eon for the largest divisions of Earth's history, namely the Hadean, Archean, Proterozoic and Phanerozoic, and these are not billion-year blocks, since the Phanerozoic covers only about 538.8 million years. With Earth about 4.54 billion years old, it is roughly 4.5 aeons old.

1 aeon = 3.1556952×10¹⁶ seconds (exactly).

Sources: Wikipedia: Aeon; Wikipedia: Geologic time scale

Month (mo)

CalendarCurrent unit

One twelfth of an average Gregorian year: 30.436875 days. Calendar months actually range from 28 to 31 days.

Month and Moon are cognates, and the unit began as the Moon's cycle of phases, about 29.53 days from one new moon to the next. The trouble is that 12 of these fall short of a solar year, so calendars have had to choose. The Islamic calendar stays purely lunar, so its year is about 11 days shorter than the solar year, while the Hebrew calendar is lunisolar, using a 19-year cycle with an extra month. Even the start of a lunar month is still debated between observing the crescent and calculating it.

Gregorian months are a compromise that drifted far from the Moon. Their lengths run from 28 to 31 days, and this site uses their mean of 30.436875 days, one twelfth of the average year. The names also keep Roman history: September to December preserve the Latin numerals for seven to ten, since they were originally the seventh to tenth months, and Quintilis and Sextilis were renamed for Julius Caesar and Augustus. When a contract says month, check whether it means a calendar month or thirty days.

1 month = 2,629,746 seconds (exactly).

Sources: Wikipedia: Month; Wikipedia: Lunar calendar

Related conversions

See all time units.