We find very few people who need to do basic arithmetic with time. But those who do REALLY need to do arithmetic. Typically, this arithmetic consists of determining how much time has elapsed between two times or finding the sum of several times. Perhaps there is even an interest in determining the length of time between two dates. These may be esoteric needs to many, but Excel "stands tall" to help you do arithmetic with time if that is what you need.
Let's build a problem where arithmetic with time could be somewhat tedious. Suppose you have people working for you that you pay by the hour. Officially, the work day is 8 hours, but some come late and some leave early. You might have a clocking system which stamps the time in and out. A typical person might have 8:15 AM and 4:55 PM. Ask yourself..."How fast could you determine the amount of time in hours and minutes this person worked?"
Excel can handle this type of problem with ease. It is all in the cell formatting and planning how you enter data.
In
this example, the time in data and time out
data are entered from the keyboard. The rest of the cells are already entered
as formulas.
Note the length of the "lunch hour".
The "trick" is in formatting Cell C2 and C3 as time with "1:30 PM" as the formatting choice. The cells C5, C6, and C7 are formatted as "13:30:55". The two formulas are entered in Cell C5 and Cell C7. This individual worked for 7 hours and 47 minutes (or at least was 'at work' for that long!) If you change the constant time for work from 48 minutes to some other time, the calculations will correctly compute by subtracting out the lunch time.