Creating a solution > About choosing a field type > About time fields
 
About time fields
Use time fields to store:
times you need to sort or search through
times used in calculation formulas or summary fields
Notes 
The separators in time fields and the order in which the time parts appear depend on the system formats set for the file and the display format for the field. For information on changing the display format for a field (for example, 11:09 PM or 23:09), see Specifying formats for time fields.
FileMaker Pro stores times as the number of seconds since midnight. Therefore you can calculate times before or after a given time by subtracting or adding a number of seconds. For example, in a calculation field whose result is a time, the following formula calculates the time one hour (60 seconds to a minute * 60 minutes to a hour = 3600 seconds) after the value in a time field named TimeStarted:
TimeStarted + 3600
Related topics 
Defining and changing fields
Working with data in time fields
Specifying formats for time fields