Months to Seconds (mo to s)
1 month equals 2,629,746 seconds exactly.
How to convert months to seconds
To convert months to seconds, multiply the number of months by 2,629,746. This factor is exact. To go the other way, multiply seconds by 3.802648621×10⁻⁷ (rounded).
seconds = months × 2,629,746
Example: 10 months = 26,297,460 seconds.
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)
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
Second (s)
The SI base unit of time, defined by the radiation frequency of the cesium-133 atom: 9,192,631,770 cycles per second.
Our word second is a leftover of Latin. Medieval scholars divided a degree, and later the hour, into 60 parts called pars minuta prima, the first small part, and divided those again into pars minuta secunda, the second small part. NIST traces the roots further back: Babylonian and Greek astronomers split the circle into 360 degrees, and around 150 C.E. Ptolemy split each degree into 60 minutes and each minute into 60 seconds. Clocks that could show seconds appeared only in the later 16th century, and Christiaan Huygens's pendulum clock of 1656 was the first able to keep time accurately to the second.
For most of history the second was a fraction of a day, and in 1956 it was redefined as a fraction of the tropical year, a definition the SI took over in 1960. In 1967 the 13th CGPM switched to atoms: 9,192,631,770 periods of the radiation tied to a hyperfine transition of caesium-133. The 2019 SI revision restated this by fixing the caesium frequency at 9,192,631,770 hertz. NIST reports that commercial caesium clocks stay within about a three-millionth of a second per year, and experimental clocks based on other atoms are roughly ten thousand times more precise.
The second is the reference unit for time on this site.
Sources: NIST: the second and the SI redefinition; BIPM: SI Brochure, 9th edition; Wikipedia: Second
Related conversions
- Seconds to months (reverse)
- Months to minutes
- Months to hours
- Months to days
- Months to weeks
- Months to years
- Months to milliseconds
- Months to microseconds
- Months to nanoseconds
- Months to decades
- Months to centuries
- Months to millennia
- Months to picoseconds
- Minutes to seconds
- Hours to seconds
- Days to seconds
- Weeks to seconds
- Years to seconds
- Milliseconds to seconds
- Microseconds to seconds
- Nanoseconds to seconds
- Decades to seconds
- Centuries to seconds
- Millennia to seconds
- Picoseconds to seconds
See all time units.