Hours Calculator
Pleasure and action make the hours seem short  when counting time it's better not to trust your intuition  use the hours calculator instead.
This Omni application includes:
 A job hours calculator (time card hour calculator);
 An add hours calculator;
 An hours from now calculator;
 An hours converter (hours to days calculator, and the like); and
 An hours difference calculator.
Add hours calculator
If you'd like to add hours, choose the first option in the first field of the hours calculator. Input your hours in the fields below, and the sum will show at the bottom. You can input negative values (to subtract hours) and change the units of time.
Example  If you know this week you worked 3 h on Monday, 6 h 45 min on Tuesday, and 7 h 55 min on Friday, you can change the units of first three fields of this add hours calculator to "hours minutes", input your numbers and get the result in hours for your payroll.
Hour converter
If you choose the second option in the first field of the hours calculator, you'll see an hours converter. Choose the unit of time and the target unit first, and input the number.
Example  If you'd like to know how many days and hours are in 235 h, leave the default setting as it is and input "235" in the second field. You should see that it equals 9 days 19 hours.
You can use this part as a minutes to hours calculator, an hours to days calculator, or other time converters you need.
Calculate hours between two times
Let's say you've worked from 9:45 am to 4:25 pm and want to check how many hours that was. In that case, choose the third option in the first field of the hours calculator. In the Start time
field, enter 9 hrs 45 min
. In the End time
field, we'll need a 24hour format  we'll get it by adding 12 hours to the PM time. In this case, it would be 4 h 25 min + 12 h = 16 h 25 min
. Once you enter the number, you'll see the result  you worked for 6 h 40 min.
Time card hour calculator
If you want to ask "How many hours did I work, calculator?", choose the fourth functionality  the weekly hours calculator. Then choose if your break is always the same length and whether you work on weekends. By default, it's an 8 hour work day calculator running from 8 am to 5 pm with a 1hour unpaid lunch. To change the hours, click the calendar icon and choose your start and end time. Alternatively, you can select the default times and type in work times in the same format.
In the advanced mode
(below the weekly hours calculator), you can set up your usual and overtime hourly rate. Once you do this, the job hour calculator will output your weekly pay.
Hours from now calculator
If you'd like to find what time it'll be in x hours, choose the fifth option in the hours calculator. Input the number of hours (or another time unit) in the first input field. If you want hours from now, leave the default date; otherwise, you need to set it yourself. The last field will output the end date (will tell you what time/date it will be some time from now).
FAQ
How to calculate hours worked?

Convert start time and end time to the 24 hour format by adding 12 hours to the PM times. E.g.
4:30 PM = 4:30 + 12:00 = 16:30
. 
Subtract the start time from the end time. E.g.,
16:30  9:00 = 7:30
. 
If your working time included an unpaid break, subtract it from the time obtained in the previous step. E.g.,
7:30  0:30 = 7:00
. 
Repeat the steps 13 for all days you want to include and sum them up. E.g., if you'd like to find your weekly hours and your schedule is the same on each day:
7 + 7 + 7 + 7 + 7 = 35
.
How many hours is part time (a day)?
Part time job requires less than 8 hours a day. In the US, there's no clear legal definition of a part time job. Part time means less than full time, in practice less than 35 hours per week and less than 7 hours per day. The exact time depends on an agreement and can vary.
How to calculate hours worked per week?

Convert all start and end times to the 24 hour format by adding 12 hours to the PM times. E.g.
7:30 PM = 7:30 + 12:00 = 19:30
. 
For each day of the week, subtract the start time from the end time. E.g.,
19:30  12:00 = 7:30
. 
If your working time included an unpaid break, subtract it from the time obtained in the previous step. E.g.,
7:30  0:30 = 7:00
. 
Add the hours obtained for each day of the week.
How to calculate overtime hours?

Determine after how many hours overtime starts. Usually overtime is the time exceeding 40 hours a week.

Calculate how many hours you've worked in a given week.

Subtract 40 hours from your weekly hours to find how long is your overtime.