This converter makes instant conversions between common units of time including seconds, minutes, hours, days, weeks, months, and years. When converting to and from month and year, this converter uses the Gregorian calendar average length of 365.2425 days in a calendar year across the complete leap cycle of 400 years. To use this converter, please select the units and provide a value to convert. The converter will make conversions as the value is being typed in.
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Time as a measurement
When we talk about measuring time, we specifically are measuring time intervals. In other words, we measure the duration that passes between two events. It is otherwise not possible to physically measure time. Today, we largely "measure," or rather, tell time using clocks, watches, computers, phones, etc. In the past, people used physical phenomena such as sunrise and sunset, the phases of the moon, and more, before developing sundials, water wheels, clocks, pendulums, and other timekeeping devices.
The most accurate clocks today are atomic clocks, which are based on cesium atoms. Cesium is a chemical element and atomic clocks measure time based on changes in the energy state of cesium.
The most widely used calendar system in the world today is the Gregorian calendar. It was first introduced in October 1852 by Pope Gregory XIII to replace the Julian calendar. The key difference between the two calendars is the difference in how leap years are spaced. In the Gregorian calendar, leap years are spaced so that the average number of days in a year is 365.2425, where every 4th year is a leap year except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. This more closely approximates the solar year than the Julian calendar did. Below is a list of common measures of time and their relationships to each other based on the Gregorian calendar average:
- 1 year = 365.2425 days
- 1 year = 12 months
- 1 year = 52.1775 weeks
- 1 day = 24 hours
- 1 day = 1,440 minutes
- 1 day = 86,400 seconds