Months to Indictions (mo to indiction)

1 month equals 0.005555555556 indictions (rounded).

1 month = 0.005555555556 indictions

How to convert months to indictions

To convert months to indictions, multiply the number of months by 0.005555555556. The factor is rounded to 10 significant digits. To go the other way, multiply indictions by 180.

indictions = months × 0.005555555556

Example: 10 months = 0.05555555556 indictions.

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

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

Indiction (indiction)

Ancient RomanHistorical unit (no longer in standard use)

A 15-year tax cycle introduced under the Roman Empire and used to date documents in the Byzantine and medieval worlds.

Indictions began as periodic reassessments of land or poll taxes in the Roman Empire, and the Latin indictio means an imposition or levy. Evidence exists for a 15-year cycle across the empire, a 14-year cycle in Roman Egypt, and a five-year cycle. Tax changes and arrears remissions tended to fall at the start of a cycle, with examples recorded under Nero in 58 AD and Hadrian in 118 AD.

Constantine is credited with turning the 15-year cycle into a dating system in 312 AD, and Egypt used it by 314 AD, though sources disagree on the first year, with one Coptic document implying 297 to 298. Justinian required indictions in dated documents in 537 AD. The year began on 23 September in the early Eastern Empire, later moving to 1 September, while Bede gives 24 September for the West and papal practice started on 25 December or 1 January. Because the length is a convention of 15 years, the figure used here is 15 Gregorian years, about 473.4 million seconds. The cycle also forms part of the 7,980-year Julian Period.

1 indiction = 473,354,280 seconds (exactly).

Sources: Wikipedia: Indiction

Related conversions

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