Hours Calculator

Use the calculators below to find the number of hours and minutes between two times. For a full time card, please use the Time Card Calculator.

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End Time: Now

Hours Between Two Dates

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RelatedTime Card Calculator | Time Calculator


An hour is most commonly defined as a period of time equal to 60 minutes, where a minute is equal to 60 seconds, and a second has a rigorous scientific definition. There are also 24 hours in a day. Most people read time using either a 12-hour clock or a 24-hour clock.

12-hour clock:

A 12-hour clock uses the numbers 1-12. Depending on the clock being used, most analog clocks or watches may not include an indication of whether the time is in the morning or evening. On digital clocks and watches, "AM" stands for anti meridiem, meaning "before midday," while "PM" stands for post meridiem, or "after noon." By convention, 12 AM denotes midnight, while 12 PM denotes noon. Using the terms "12 midnight" and "12 noon" can remove ambiguity in cases where a person may not be accustomed to conventions.

24-hour clock:

A 24-hour clock typically uses the numbers 0-23, where 00:00 indicates midnight, and a day runs from midnight to midnight over the course of 24 hours. This time format is an international standard, and is often used to avoid the ambiguity resulting from the use of a 12-hour clock. The hours from 0-11 denote what would be the AM hours on a 12-hour clock, while hours 12-23 denote the PM hours of a 12-hour clock. In certain countries, 24-hour time is referred to as military time, since this is the time format used by militaries (and other entities) around the world, where unambiguous time measurement is particularly important.


Hours in different time periods

DescriptionHours
Hours in a day24
Hours in a week168
Hours in a month672 for a 28-day month
696 for a 29-day month
720 for a 30-day month
744 for a 31-day month
730.5 on average
Hours in a year8,760 for a 365-day year
8,784 for a 366-day year
8,766 on average
Hours in a decade87,648 for a 2-leap-year decade
87,672 for a 3-leap-year decade
87,660 on average
Hours in a century876,600