Tun (Maya) to Months (tun to mo)

1 tun (Maya) equals 11.82775827 months (rounded).

1 tun (Maya) = 11.82775827 months

How to convert tun (Maya) to months

To convert tun (Maya) to months, multiply the number of tun (Maya) by 11.82775827. The factor is rounded to 10 significant digits. To go the other way, multiply months by 0.084546875.

months = tun (Maya) × 11.82775827

Example: 10 tun (Maya) = 118.2775827 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

Tun (Maya) (tun)

MayaHistorical unit (no longer in standard use)

18 winals or 360 days, the Maya 'year' of the Long Count.

Eighteen winals, or 360 days, make a tun. Scholars often call it the Long Count year, but it is five days shorter than the 365-day civil year, the haabʼ, and about five and a quarter days shorter than the tropical year of roughly 365.24 days. The tun therefore drifts away from the seasons, and the Maya tracked the solar year separately with the haabʼ.

The tun is the third position from the right in a written Long Count date. Its choice of 18 winals is the reason the system is not purely base-20: a strict base-20 count would have given 400 days at this step. The rounded 360-day figure is close to a year while staying a multiple of 20, which suited arithmetic on 20-day units.

The tun is the building block of the longer cycles. Twenty tuns form a katun, and rulers and events were frequently dated by how many tuns had passed. In seconds it equals 31,104,000, about 0.99 of a modern calendar year.

1 tun (Maya) = 31,104,000 seconds (exactly).

Sources: Wikipedia: Maya calendar; Wikipedia: Mesoamerican Long Count calendar; Steve Morse: Mayan Calendar Rules

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

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