Time is traditionally expressed in hours, minutes and seconds. This format is convenient for general use, but is inappropriate in mathematical operations. Calculations typically require the expression of a time interval in decimal form. For instance, 30 minutes equal 0.5 hour and 45 seconds equal 0.75 minute. As an example, we will convert 5 hours, 27 minutes, 56 seconds to decimal form.

Record the integer number of hours of the time given. In this example, it is 5.

Divide the number of minutes by 60 to convert them into a fraction of an hour. In our example, it is 27/60 = 0.45.

Divide the number of seconds by 3,600 to calculate them as a fraction of an hour. This is because there are 60 seconds in a minute and 60 minutes in an hour. In our example we have 56/3600= 0.0156.

Sum the values from Steps 1 to 3 to obtain the answer. In our example, 5 hours, 27 minutes, 56 seconds corresponds to 5 + 0.45 + 0.0156 = 5.4656 hours.