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.
Time Calculator
Hours Between Two Dates
About Hours
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 ante 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
| Description | Hours |
|---|---|
| Hours in a day | 24 |
| Hours in a week | 168 |
| Hours in a month | 672 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 year | 8,760 for a 365-day year 8,784 for a 366-day year 8,766 on average |
| Hours in a decade | 87,648 for a 2-leap-year decade 87,672 for a 3-leap-year decade 87,660 on average |
| Hours in a century | 876,600 |
Hours Calculator
Use the calculators below to determine the number of hours and minutes between two times. For detailed work schedules, use the Time Card Calculator.
Modify the values and click “Calculate” to see results.
Start Time:
8:30 AM
Now | Swap
End Time:
5:30 PM
Now
Hours Between Two Dates
Start Time:
February 20, 2025
Select Calendar
8:30 AM
Now
End Time:
February 20, 2025
Select Calendar
5:30 PM
Now
Related Tools
- Time Card Calculator
- Time Calculator
Understanding Hours
An hour is defined as a period of 60 minutes, where a minute equals 60 seconds. A day consists of 24 hours. Time is commonly read using either a 12-hour clock or a 24-hour clock.
12-Hour Clock
- Uses numbers 1-12.
- AM (ante meridiem) means “before midday,” and PM (post meridiem) means “after noon.”
- 12 AM represents midnight, and 12 PM represents noon.
- Terms like “12 midnight” and “12 noon” help avoid confusion.
24-Hour Clock
- Uses numbers 0-23, where 00:00 indicates midnight.
- A full day runs from 00:00 to 23:59.
- Hours 0-11 correspond to AM, and hours 12-23 correspond to PM on a 12-hour clock.
- Often called military time in some countries, as it eliminates ambiguity.
Hours in Different Time Periods
| Description | Hours |
|---|---|
| Hours in a day | 24 |
| Hours in a week | 168 |
| Hours in a month | 672 (28-day month) |
| 696 (29-day month) | |
| 720 (30-day month) | |
| 744 (31-day month) | |
| 730.5 (average) | |
| Hours in a year | 8,760 (365-day year) |
| 8,784 (366-day year) | |
| 8,766 (average) | |
| Hours in a decade | 87,648 (2-leap-year decade) |
| 87,672 (3-leap-year decade) | |
| 87,660 (average) | |
| Hours in a century | 876,600 |
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Whether you’re calculating work hours, planning schedules, or exploring time concepts, this tool simplifies the process. For more advanced time tracking, check out the Time Card Calculator.