Time Duration Calculator
Free time duration calculator. Calculate hours, minutes, seconds between times. Add or subtract time intervals easily.
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Last updated: January 2026
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Frequently Asked Questions
How do I calculate the duration between two times?
Subtract the start time from the end time. Convert to the same unit first. Example: 2:30 PM to 5:45 PM = 5h 45m - 2h 30m = 3 hours 15 minutes. If crossing midnight, add 24 hours to the end time before subtracting. Our calculator handles this automatically.
How do I add or subtract time from a given time?
Convert everything to the same unit (minutes or seconds), perform the operation, then convert back. Example: 10:45 AM + 2 hours 30 minutes = 10:45 + 2:30 = 13:15 (1:15 PM). For subtraction crossing midnight backward, subtract 24 hours from the result.
How do I convert between hours, minutes, and seconds?
Use these conversions: 1 hour = 60 minutes = 3,600 seconds. 1 minute = 60 seconds. To convert 2.5 hours to minutes: 2.5 × 60 = 150 minutes. To convert 150 minutes to hours: 150 ÷ 60 = 2.5 hours. For seconds: multiply by 3600 or divide by 3600.
What does 'crosses midnight' mean in time calculations?
When your time span goes past 12:00 AM (midnight), it 'crosses midnight.' Example: 10:00 PM to 2:00 AM crosses midnight. The duration is calculated as (24:00 - 22:00) + 2:00 = 4 hours. This is common for night shifts, overnight events, or international time zone calculations.
How do I calculate time for payroll or timesheets?
Sum all work periods, subtracting breaks. Example: Clocked in 8:30 AM, lunch 12:00-12:30 PM, clocked out 5:00 PM. Morning: 12:00 - 8:30 = 3h 30m. Afternoon: 5:00 - 12:30 = 4h 30m. Total: 8 hours. For overtime, subtract standard hours (usually 8) from the total.