What time would 15 hours be?

4am

16 hours from 1pm

11pm

16 hours from 8am

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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.

Hours Between Two Dates

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

Use this calculator to easily calculate the hour difference between any given two times within a day, accurate to the minute. It will also show you the result in minutes, if an hour calculation is not convenient for you. If you wonder how many hours you spend on certain activities (e.g. How many hours am I working?), this is the hours calculator for you.

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This simple online tool makes it easy to calculate the difference in hours and minutes between two given times. To calculate the hours and minutes contained in a time period you need to know its beginning and end. The hours calculator will use the time format depending on your browser locale settings, e.g. US, UK.

After you enter the beginning and the end of the time period you are interested in, you simply click the "Calculate difference" button. Below you will get the difference in both full hours and in minutes. If the first hour you enter is later in the day than the second hour you enter, the time difference is calculated as if the first hour is for today and the second is tomorrow. For example, entering a start time of 6PM and end time of 8AM in the calculator, it will calculate the difference in hours, minutes, and seconds from 6PM today to 8AM tomorrow (14 hours).

This calculator for the number of hours between two times could be used to find out for how long you have worked in order to fill in time sheets. For example, how many hours are there between 9 and 5:30 pm (or 9:00 and 17:30)? You simply need to enter the two times in any order and click on "Calculate". The result will be 8 hours 30 minutes (8:30 hours or 8.5 hours in decimal) or 510 minutes. There are 8 full hours between these times. It also supports the subtraction of lunch breaks and other types of pauses from the total hours in between. For more on that see lunch breaks.

    How many hours?

Many people working a job with regular hours want to find out the duration of their work day. If you're also wondering "how many hours am I working?" and you are on a 9AM to 5PM job, then the question is how many hours is 9 to 5. The answer is exactly eight hours.

If you leave your kids early at school and pick them up in the afternoon, you might wonder how much time they spend in school each day. If you leave them at 7AM and pick them up at 3PM then the question is how many hours is 7AM to 3PM and the answer is eight hours (15-7 = 8).

Here are some more examples of calculating how many hours are between two specified points in time. You can use our hours calculator above to compute the time between any two arbitrary hours and minutes.

Working hours with lunch break excluded

If you are using our calculator to understand how many hours you are working, then you need to use the functionality which allows the subtraction of a lunch break or other types of shift breaks to get just the number of working hours. For example, a 7:30 to 4:30 work day with a 30 minute lunch break means an 8.5 hour work day (9 hours in between, minus 30 minutes or 0.5 hours equals 8.5). If you are working shifts your break may not be a lunch break, and you may also have multiple breaks allowed. In such a case add up the total amount of time off and enter it in the field (in minutes).

The ability to specify the total break time is also useful if calculating physical activity with break intervals, e.g. an intensive training for one hour followed by a 15 minute break and then another hour of exercise.

    American vs. European time

The way Europeans and Americans tell time is different, both in the way it is said and in the way it is written. Civilians in America use the hours until 12 two times in a day, while Europeans go between 00:00 and 23:59. For this reason in America people would use pm and am to distinguish what half of the day they are talking about. On the other hand, most Europeans would probably say 15:00 o’clock (instead of 3 pm). To make it even more complicated for guests from overseas though, many Europeans would also say 3 in the afternoon.

If you are new to Europe and need to deal with "military time", all you have to do is use the hours until 12 in the same way and for after 1 pm either add or subtract 12, putting pm after the result. For example, if you are meeting someone at 17:30, that would be 17:30 – 12 = 5:30 pm. If you need to find out what to write to a colleague you want to meet at 2pm, this would be 2 + 12 = 14 pm.

For the sake of accuracy, it should be noted that, although similar to it, European time telling is not exactly military time. In the military 18:00 (6 pm) would be 1800. In one case it is "eighteen o’clock", in the other it is "eighteen hundred". In the military 7:00 (7 am) would be "zero seven hundred" or "oh seven hundred" (0700), while civilians in Europe would just say "seven". The stricter military way of communicating time is necessitated by the critical conditions in which it is used. Mistaking the hour or minute of an action could result in lost lives...