Time Duration Calculator

Step 1: Enter the start time in 24-hour format (HH:MM). For example, 09:15 for 9:15 AM or 14:30 for 2:30 PM.

Step 2: Enter the end time in 24-hour format. For example, 17:45 for 5:45 PM.

Step 3: Click Calculate. The result shows the duration in hours and minutes, along with total minutes. If the end time is earlier than the start time, the calculator assumes the shift crosses midnight and adds 24 hours.

Time duration is the amount of time between two clock readings. Unlike time addition (which combines two durations), time duration answers the question "how long was this?" — from a starting clock time to an ending clock time.

The key difference from the time calculator: The time calculator adds or subtracts two time durations (like 2h30m + 1h45m). The time duration calculator finds the elapsed time between two clock times (like 9:15 AM to 5:45 PM). Both work with hours and minutes, but they answer different questions.

24-hour format eliminates AM/PM confusion. In this format, 0:00 is midnight, 12:00 is noon, 13:00 is 1 PM, and 23:59 is one minute before midnight. Using 24-hour format is especially important for overnight calculations where AM/PM distinctions matter.

Overnight durations are common in shift work, travel, and cooking. If you start at 22:00 (10 PM) and end at 06:00 (6 AM), the duration is 8 hours, not −16 hours. The calculator detects this case and handles it automatically by adding 24 hours.

Common uses: Tracking meeting lengths, calculating shift hours, timing cooking and baking, measuring travel time, logging study sessions, and recording exercise duration.

Duration = End Time − Start Time

Convert both times to minutes from midnight, subtract, then convert back.

Step 1: Convert to minutes.
Start Minutes = Start Hours × 60 + Start Minutes
End Minutes = End Hours × 60 + End Minutes

Step 2: Subtract.
Duration (minutes) = End Minutes − Start Minutes

Step 3: If negative (overnight), add 1,440 (24 hours in minutes).
If Duration < 0: Duration = Duration + 1,440

Step 4: Convert back.
Hours = floor(Duration / 60)
Minutes = Duration mod 60

Example: Start 09:15, End 17:45.
- Start: 9 × 60 + 15 = 555 minutes
- End: 17 × 60 + 45 = 1,065 minutes
- Duration: 1,065 − 555 = 510 minutes
- Hours: floor(510/60) = 8, Minutes: 510 mod 60 = 30
- Result: 8 hours 30 minutes

Example 1: Work Shift Duration
You start at 09:00 and finish at 17:30. Enter 09:00 and 17:30. Result: 8 hours 30 minutes (510 total minutes). Subtract your lunch break mentally for net work time.

Example 2: Overnight Duration
A flight departs at 23:30 and arrives at 07:15 the next morning. Enter 23:30 and 07:15. Result: 7 hours 45 minutes. The calculator correctly handles the midnight crossover.

Example 3: Quick Meeting
A meeting runs from 14:15 to 15:50. Enter 14:15 and 15:50. Result: 1 hour 35 minutes (95 total minutes).

Use 24-hour format to avoid mistakes. 5:00 could be morning or afternoon. 17:00 is always 5 PM. Add 12 to any PM hour: 1 PM = 13:00, 5 PM = 17:00, 11 PM = 23:00. Midnight is 00:00, noon is 12:00.

Overnight calculations work automatically. If your end time is earlier than your start time, the calculator assumes the shift crossed midnight. A start of 22:00 and end of 06:00 gives 8 hours, not an error.

For decimal hours, divide minutes by 60. If the result is 8 hours 30 minutes and you need decimal hours: 30 ÷ 60 = 0.5, so 8.5 hours. For 45 minutes: 45 ÷ 60 = 0.75, so 8.75 hours.

This calculator does not subtract breaks. The result is the total elapsed time. If you need to subtract a lunch break, use the Time Calculator (which can subtract durations) or the Time Clock Calculator (which has a break field).

For multiple time segments, calculate each separately. Morning meeting (09:00-10:30) = 1h 30m. Afternoon meeting (14:00-16:15) = 2h 15m. Total: 3h 45m.