Time Unit Conversion Table


fractions of a second
metric name
0,000 000 000 000 000 000 000 001
yoctosecond [ ys ]
0,000 000 000 000 000 000 001
zeptosecond [ zs ]
0,000 000 000 000 000 001
attosecond [ as ]
0,000 000 000 000 001
femtosecond [ fs ]
0,000 000 000 001 [ trillionth ]
picosecond [ ps ]
0,000 000 001 [ billionth ]
nanosecond [ ns ]
0,000 001 [ millionth ]
microsecond [ µs ]
0,001 [ thousandth ]
millisecond [ ms ]
0.01 [ hundredth ]
centisecond [ cs ]
1.0
second [ s ]
seconds to years

60 seconds
1 minute [ mean solar ]
59.83617 seconds
1 minute [ sidereal ]
60 minutes
1 hour
24 hours
1 day
3,600 seconds
1 hour
86,400 seconds
1 day [ mean solar ]
86,164.09 seconds
1 day [ sidereal ]
7 days
1 week
168 hours
1 week
14 days
1 fortnight
28, 29, 30 or 31 days
1 month
365 days
1 year
366 days
1 leap year
12 months
1 year
31,536,000 seconds
1 year [ calendar ]
31,558,150 seconds
1 year [ sidereal ]
31,556,930 seconds
1 year [ tropical ]
9,460,550,000,000,000 metres
1 light year
299,792,458 metres per second ( m/s )
speed of light
parsec
approx. 3.25 light years
year intervals - anniversaries
number of years
Biennial
2
Triennial
3
Quadrennial
4
Quinquennial
5
Hexennial
6
Septennial
7
Octennial
8
Novennial
9
Decennial
10

Time Unit Conversion Chart

Unit
Symbol
Definition
Conversion to SI units
atomic unit of time
au
a0/(a·c)
~ 2.418 884 254 x 10-17 s
Callippic cycle

441 mo (hollow) + 499 mo (full) = 76 a of 365.25 d
2.398 3776 x 109 s
century
c
100 a (see below for definition of year length)
100 x year
day
d
24 h
86400 s
day (sidereal)
d
Time needed for the Earth to rotate once around its axis, determined from successive transits of a very distant astronomical object across an observer's meridian (International Celestial Reference Frame)
~ 86 164.1 s
decade
dec
10 a (see below for definition of year length)
10 x year
fortnight
fn
2 wk
1 209 600 s
helek

1/1 080 h
3.3 s
Hipparchic cycle

4 Callippic cycles - 1 d
9.593 424 x 109 s
hour
h
60 min
3 600 s
jiffy
j
1/60 s
.016 s
jiffy (alternate)
ja
1/100 s
10 ms
ke (quarter of an hour)

¼ h = 1/96 d
60 x 60 / 4 s = 900 s = 60 / 4 min = 15 min
ke (traditional)

1/100 d
24 x 60 x 60 / 100 s = 864 s = 24 * 60 / 100 min = 14.4 min
lustre; lustrum

5 a of 365 d
1.5768 x 108 s
Metonic cycle; enneadecaeteris

110 mo (hollow) + 125 mo (full) = 6940 d ~ 19 a
5.996 16 x 108 s
millennium

1 000 a (see below for definition of year length)
1000 x year
milliday
md
1/1 000 d
24 x 60 x 60 / 1 000 s = 86.4 s
minute
min
60 s, due to leap seconds sometimes 59 s or 61 s,
60 s
moment

90 s
90 s
month (full)
mo
30 d
2 592 000 s
month (Greg. av.)
mo
Average Gregorian month = 365.2425/12 d = 30.436875 d
~ 2.6297 x 106 s
month (hollow)
mo
29 d
2 505 600 s
month (synodic)
mo
Cycle time of moon phases ~ 29.530589 days (Average)
~ 2.551 x 106 s
octaeteris

48 mo (full) + 48 mo (hollow) + 3 mo (full) = 8 a of 365.25 d = 2922 d
2.524 608 x 108 s
Planck time

(G?/c5)½
~ 1.351 211 868 x 10-43 s
second
s
time of 9 192 631 770 periods of the radiation corresponding to the transition between the 2 hyperfine levels of the ground state of the caesium 133 atom at 0 K (but other seconds are sometimes used in astronomy)
(SI base unit)
shake

10-8 s
10 ns
sigma

10-6 s
1 µs
Sothic cycle

1 461 a of 365 d
4.607 4096 x 1010 s
svedberg
S
10-13 s
100 fs
week
wk
7 d
604 800 s
year (Gregorian)
a, y, or yr
365.2425 d average, calculated from common years (365 d) plus leap years (366 d) on most years divisible by 4. See leap year for details.
31 556 952 s
year (Julian)
a, y, or yr
365.25 d average, calculated from common years (365 d) plus one leap year (366 d) every four years
31 557 600 s
year (sidereal)
a, y, or yr
time taken for Sun to return to the same position with respect to the stars of the celestial sphere
~ 365.256 363 d ~ 31 558 149.7632 s
year (tropical)
a, y, or yr
Length of time it takes for the Sun to return to the same position in the cycle of seasons
~ 365.242 190 d ~ 31 556 925 s
Where UTC is observed, the length of time units longer than 1 s may increase or decrease by 1 s if a leap second occurs during the time interval of interest.
Source: http://en.wikipedia.org/wiki/Unit_conversion
Source: Time Unit Converter