…
Use the calculator to convert time units for day, quarter, hour, week, year, etc.
Unit | Definition |
millennium | 1,000 years |
century | 100 years |
decade | 10 years |
year (average) | 365.242 days or 12 months |
common year | 365 days or 12 months |
leap year | 366 days or 12 months |
quarter | 3 months |
month | 28-31 days Jan., Mar., May, Jul., Aug. Oct., Dec.—31 days Apr., Jun., Sep., Nov.—30 days. Feb.—28 days for common year and 29 days for leap year |
week | 7 days |
day | 24 hours or 1,440 minutes or 86,400 seconds |
hour | 60 minutes or 3,600 seconds |
minute | 60 seconds |
second | base unit |
millisecond | 10^{-3} second |
microsecond | 10^{-6} second |
nanosecond | 10^{-9} second |
picosecond | 10^{-12} second |
Unit | Length, Duration and Size | Notes |
---|---|---|
Planck time unit | 5.39×10^{−44} s | The amount of time light takes to travel one Planck length. Theoretically, this is the smallest time measurement that will ever be possible.^{[3]} Smaller time units have no use in physics as we understand it today. |
yoctosecond | 10^{−24} s | |
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 | Time measurement scale of the NIST strontium atomic clock. Smallest fragment of time currently measurable is 850 zeptoseconds.[1]^{[3]} |
attosecond | 10^{−18} s | |
femtosecond | 10^{−15} s | Pulse time on fastest lasers. |
Svedberg | 10^{−13} s | Time unit used for sedimentation rates (usually of proteins). |
picosecond | 10^{−12} s | |
nanosecond | 10^{−9} s | 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 | Symbol is µs |
millisecond | 10^{−3} s | Shortest time unit used on stopwatches. |
jiffy (electronics) | 1/60 s or 1/50 s | Used to measure the time between alternating power cycles. Also a casual term for a short period of time. |
second | 1 s | SI Base unit. |
minute | 60 s | |
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]} |
ke | 14 min 24 s | Usually calculated as 15 minutes, similar to "quarter" as in "a quarter past six" (6:15). |
kilosecond | 1000 s | 16 minutes and 40 seconds |
hour | 60 min | |
day | 24 h | Longest unit used on stopwatches and countdowns. |
week | 7 d | Also called "sennight". |
megasecond | 10^{6} s | 277.777778333333 hours or about 1 week and 4.6 days. |
fortnight | 2 weeks | 14 days |
lunar month | 27 d 4 h 48 min – 29 d 12 h | Various definitions of lunar month exist. |
month | 28–31 d | Occasionally calculated as 30 days. |
quarter and season | 3 mo | |
semester | 18 weeks | A division of the academic year.^{[5]} Literally "six months", also used in this sense. |
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 |
biennium | 2 yr | |
triennium | 3 yr | |
quadrennium | 4 yr | |
olympiad | 4 yr | |
lustrum | 5 yr | |
decade | 10 yr | |
indiction | 15 yr | |
gigasecond | 10^{9} s | 16,666,666.6667 minutes or About 31.7 years. |
jubilee | 50 yr | |
century | 100 yr | |
millennium | 1000 yr | Also called "kiloannum". |
terasecond | 10^{12} s | 16,666,666,666.6667 minutes or about 31,700 years. |
Megannum | 10^{6} yr | Also called "Megayear." About 1,000 millennia (plural of millennium), or 1 million years. |
petasecond | 10^{15} s | About 31,700,000 years |
galactic year | 2.3×10^{8} yr^{[2]} | The amount of time it takes the Solar System to orbit the center of the Milky Way Galaxy one time. |
cosmological decade | varies | 10 times the length of the previous cosmological decade, with CÐ 1 beginning either 10 seconds or 10 years after the Big Bang, depending on the definition. |
aeon | 10^{9} yr | Also spelled "eon". Also refers to an indefinite period of time. |
exasecond | 10^{18} s | About 31,700,000,000 years or 380,399,583,123.74 months |
zettasecond | 10^{21} s | About 31.7 trillion years or 3,803,995,983,123,744.56 months |
yottasecond | 10^{24} s | About 31.7 quadrillion years or 380,399,583,123,744,510 months |
Program testing can be a very effective way to show the presence of bugs, but is hopelessly inadequate for showing their absence.
Edsger Dijkstra
…
…