Name
|
Length
|
Notes
|
Planck time |
5.39×10−44 s |
The amount of time light takes to travel one Planck length.
|
quectosecond |
10−30 s |
One nonillionth of a second.
|
rontosecond |
10−27 s |
One octillionth of a second.
|
yoctosecond |
10−24 s |
One septillionth of a second.
|
jiffy (physics) |
3×10−24 s |
The amount of time light takes to travel one fermi (about the size of a nucleon) in a vacuum.
|
zeptosecond |
10−21 s |
One sextillionth of a second. Time measurement scale of the NIST strontium atomic clock. Smallest fragment of time currently measurable is 247 zeptoseconds.[3]
|
attosecond |
10−18 s |
One quintillionth of a second.
|
femtosecond |
10−15 s |
One quadrillionth of a second. Pulse time on fastest lasers.
|
Svedberg |
10−13 s |
Time unit used for sedimentation rates (usually of proteins).
|
picosecond |
10−12 s |
One trillionth of a second.
|
nanosecond |
10−9 s |
One billionth of a second. Time for molecules to fluoresce.
|
shake |
10−8 s |
10 nanoseconds, also a casual term for a short period of time.
|
microsecond |
10−6 s |
One millionth of a second. Symbol is μs
|
millisecond |
10−3 s |
One thousandth of a second. Shortest time unit used on stopwatches.
|
jiffy (electronics) |
~10−3 s
|
Used to measure the time between alternating power cycles. Also a casual term for a short period of time.
|
centisecond |
10−2 s |
One hundredth of a second.
|
decisecond |
10−1 s |
One tenth of a second.
|
second |
1 s |
SI base unit for time.
|
decasecond |
10 s |
Ten seconds (one sixth of a minute)
|
minute |
60 s |
|
hectosecond |
100 s |
|
milliday |
1/1000 d |
Also marketed as a ".beat" by the Swatch corporation.
|
moment |
1/40 solar hour (90 s on average) |
Medieval unit of time used by astronomers to compute astronomical movements, length varies with the season.[4] Also colloquially refers to a brief period of time.
|
kilosecond |
103 s |
About 17 minutes.
|
hour |
60 min |
|
day |
24 h |
Longest unit used on stopwatches and countdowns.
|
week |
7 d |
Historically sometimes also called "sennight".
|
megasecond |
106 s |
About 11.6 days.
|
fortnight |
2 weeks |
14 days
|
lunar month |
27 d 4 h 48 min – 29 d 12 h |
Various definitions of lunar month exist; sometimes also called a "lunation."
|
month |
28–31 d |
Occasionally calculated as 30 days.
|
quarantine
|
40 d (approximately 5.71 weeks)
|
To retain in obligatory isolation or separation, as a sanitary measure to prevent the spread of contagious disease. Historically it meant to be isolated for 40 days. From Middle English quarentine, from Italian quarantina (“forty days”), the period Venetians customarily kept ships from plague-ridden countries waiting off port, from quaranta (“forty”), from Latin quadrāgintā.
|
semester |
18 weeks |
A division of the academic year.[5] Literally "six months", also used in this sense.
|
lunar year |
354.37 d |
|
year |
12 mo |
365 or 366 d
|
common year |
365 d |
52 weeks and 1 day.
|
tropical year |
365 d 5 h 48 min 45.216 s[6] |
Average.
|
Gregorian year |
365 d 5 h 49 min 12 s |
Average.
|
sidereal year |
365 d 6 h 9 min 9.7635456 s
|
leap year |
366 d |
52 weeks and 2 d
|
olympiad |
4 yr |
A quadrennium (plural: quadrennia or quadrenniums) is also a period of four years, most commonly used in reference to the four-year period between each Olympic Games.[7] It is also used in reference to the four-year interval between leap years, for example when wishing friends and family a "happy quadrennium" on February 29.[citation needed]
|
lustrum |
5 yr |
In early Roman times, the interval between censuses.
|
decade |
10 yr |
|
indiction |
15 yr |
Interval for taxation assessments (Roman Empire).
|
gigasecond |
109 s |
About 31.7 years.
|
jubilee |
50 yr
|
|
century |
100 yr |
|
millennium |
1000 yr |
Also called "kiloannum".
|
Age |
2,148 and two thirds of a year |
a unit used in astrology, each of them represent a star sign
|
terasecond |
1012 s |
About 31,709 years.
|
megaannum |
106 yr |
Also called "Megayear." 1,000 millennia (plural of millennium), or 1 million years (in geology, abbreviated as Ma).
|
petasecond |
1015 s |
About 31,709,791 years.
|
galactic year |
2.3×108 yr |
The amount of time it takes the Solar System to orbit the center of the Milky Way Galaxy (approx 230,000,000 years[2]).
|
cosmological decade |
logarithmic (varies) |
10 times the length of the previous cosmological decade, with CD 1 beginning either 10 seconds or 10 years after the Big Bang, depending on the definition.
|
eon |
109 yr |
Also refers to an indefinite period of time, otherwise is 1,000,000,000 years.
|
kalpa |
4.32×109 yr |
Used in Hindu mythology. About 4,320,000,000 years.
|
exasecond |
1018 s |
About 31,709,791,983 years. Approximately 2.3 times the current age of the universe.
|
zettasecond |
1021 s |
About 31,709,791,983,764 years.
|
yottasecond |
1024 s |
About 31,709,791,983,764,586 years.
|
ronnasecond |
1027 s |
About 31,709,791,983,764,586,504 years.
|
quettasecond |
1030 s |
About 31,709,791,983,764,586,504,312 years.
|