Time Duration Calculator

Calculating the duration between two clock times requires converting both times to a common reference (typically minutes from midnight), finding the difference, and handling the special case where the end time is the next day. For same-day calculations, the duration is simply the end time minus the start time. When the end time is earlier than the start time (indicating a midnight crossing), add 1440 (the number of minutes in a day) to the end time before subtracting. The 24-hour clock system eliminates AM/PM ambiguity. In this system, midnight is 0:00, noon is 12:00, 1:00 PM is 13:00, and 11:59 PM is 23:59. This format is standard in military, aviation, medical, and international contexts. Decimal hours are often required for payroll and billing systems. To convert minutes to decimal hours, divide by 60. For example, 8 hours 30 minutes = 8.5 decimal hours, and 7 hours 45 minutes = 7.75 decimal hours. Common conversions include: 15 minutes = 0.25, 30 minutes = 0.50, and 45 minutes = 0.75. Time zones add complexity to duration calculations. If the start and end times are in different time zones, you must first convert both to the same zone (typically UTC) before calculating the duration. Daylight saving time transitions can also add or subtract an hour from the expected duration.