Convert between different units of time including seconds, minutes, hours, days, weeks, months, and years.
The modern definition of a second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom.
A leap year occurs every 4 years to account for the fact that Earth's orbit around the Sun takes approximately 365.25 days. However, years divisible by 100 are not leap years unless they are also divisible by 400.
There are 24 primary time zones on Earth, each approximately 15 degrees of longitude wide. The most extreme time difference between two places on Earth is 26 hours between the Kiribati Line Islands and Baker Island.
The most accurate atomic clocks are so precise that they would neither gain nor lose a second in over 100 million years. They're used for GPS satellites, telecommunications, and defining international time standards.