Hours Calculator

1. How to calculate hours between times
• Hours to decimal hours conversion
2. How many hours?
• Working hours with break excluded
3. Number of hours in different time periods
• Hours in a year
• Number of hours in a month
• How many hours in a week
4. American vs. European time

    How to calculate hours between times

This simple online tool makes it easy to work out the difference in hours and minutes between two given times, for example the start and end of a work day or shift. To find the number of hours in a time period specify its beginning and end by entering them in the respective fields. The hours calculator will use the time format specified on your browser locale settings, e.g. US, UK.

Afterwards, simply click the "Calculate hours" button. The resulting output includes the difference in both full hours and in minutes. Note that if the first hour you enter is later in the day than the second hour you enter, the time difference is computed as if the first hour is for today and the second is tomorrow. For example, if you enter a start time and end time of 6PM and 8AM, the calculator will return the difference in hours, minutes, and seconds overnight: from 6PM today to 8AM tomorrow (14 h.).

If you need to fill in timesheets, you can use the tool to find out how long you have worked in a day. For example, how many hours are there between 9 and 5:30 pm (or 9:00 and 17:30)? Simply enter the two times in any order and click "Calculate". The result is 8 hours 30 minutes (8:30 or 8.5 h. in decimal), so the time between these two times is 510 minutes. There are eight full hours between the times.

The calculator also supports the subtraction of lunch breaks and other types of pauses from the total time in between. For more on that see lunch breaks.

Hours to decimal hours conversion

This calculator for the hours between two times automatically displays decimal hours between times, but if you need to convert digital hours and minutes (hh:ss) into decimal (h.), the math is simple: divide the number of minutes by 60 to get the decimal part, then append it to the number of hours. For example, 8:15 is 8.25 in decimal since there are eight full hours and 15 minutes divided by 60 equals 0.25. You can also try our digital time converter.

    How many hours?

Many people working a job with a regular schedule want to find out the duration of their work day or work shift. If you're also wondering "how many hours am I working?" and if you are on a 9AM to 5PM job, then the question is one of time between times, or simply 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 "7AM to 3PM is how many hours" and the answer is eight hours (15-7 = 8).

Here are some more examples of calculating hours between points in time.

To answer a question like "7am to 3pm is how many hours", just look up the corresponding row and check the corresponding time in hours and minutes, or in decimal hours. You can also use our hours calculator to compute the time between any two times.

Working hours with break excluded

When trying to find out how many hours you are working, you may need to subtract a lunch break or other types of shift breaks in order to get the correct 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 h, in between, minus 30 minutes or 0.5 h. equals 8.5).

If you are working shifts your break may not be a lunch break and you may have multiple breaks allowed. If that is the case, to calculate your work hours with all breaks excluded first add up the total amount of time off and enter it in the "Break time" field (in minutes). For a more detailed timesheet calculation, consider using our advanced work hours calculator

The ability to specify the total break time is also useful if calculating physical activity with break intervals. An example would be intensive training session for one hour followed by a 15 minute break and then another hour of exercise.

    Number of hours in different time periods

While calculating the number of hours between two times within a day is often of interest, sometimes longer time periods may be of interest like weeks, months, and years. All such calculations are based on a day having 24 hours, counting the number of days in the respective period and multiplying it by 24.

Hours in a year

A calendar year has 8,766 hours, on average. A non-leap year has 8,760 hours (365 days), while a leap year has 8,784 hours (366 days). The calculation is 365 · 24 = 8,760, and 366 · 24 = 8,784, accordingly.

Number of hours in a month

A calendar month has 730.5 hours, on average. Since months have different numbers of days, each month has a different number of hours:

• There are 744 hours in the months of January, March, May, July, August, October, and December
• There are 720 hours in the months of April, June, September, and November
• February has 672 hours in a non-leap year and 696 in a leap year

How many hours in a week

A week is defined as having seven days and since a day has twenty four hours, a week has exactly 168 hours. The calculation is 7 · 24 = 168. The number of work hours in a week depends on the number of working days and how long each day is. For example, a five-day work week with each work day being 8 hours long is 40 work hours. With just 7 working hours per day, a five-day work week would amount to 35 working hours.

    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.. Arguably, using a 24h format makes counting hours between times easier, especially for calculating time worked as it often crosses from AM to PM. See our 24 hour clock converter page for more.

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 07:00 (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...