Time Duration Calculator
Calculate elapsed hours, minutes, and decimal time with overnight shift and break support.
Deducted from the total duration (e.g. 30 for lunch break).
Time Duration Calculation Methodology
The Time Duration Calculator computes the elapsed duration between two clock times in hours and minutes, total minutes, and decimal hours, with overnight shift and break deduction support.
Calculates time-of-day interval differences on a 24-hour clock. When end time is earlier than start time (or when declared as overnight), the duration correctly wraps across midnight (1,440 minutes in a full day). Optional break minutes are deducted from gross duration to determine net working time.
Clock Conventions & Break Rules
- Operates on a 24-hour clock interval without timezone shifts or daylight saving time adjustments.
- When start and end times are identical, the user can choose between 0 hours and 24 hours.
- Break deduction cannot exceed gross duration.
Start at 10:30 PM, end at 1:15 AM the next day, zero break.
Start: 22:30 (1,350 minutes from midnight).
End: 01:15 (75 minutes from midnight).
Overnight calculation: (1,440 - 1,350) + 75 = 90 + 75 = 165 minutes.
Conversion: 165 minutes = 2 hours and 45 minutes = 2.75 decimal hours.
Result: 2 hours 45 minutes (2.75 decimal hours).
Start at 8:00 AM, end at 4:30 PM, 30-minute unpaid lunch break.
Gross interval: 8:00 to 16:30 = 8 hours 30 minutes (510 minutes).
Deduct break: 510 - 30 = 480 minutes.
Net working duration: 480 minutes = 8 hours 0 minutes (8.00 decimal hours).
Result: 8 hours 0 minutes net (8.0 decimal hours).
Frequently Asked Questions
How do I calculate a night shift that crosses midnight?
Enter your start time (e.g. 10:30 PM) and end time (e.g. 6:30 AM). If end time is earlier than start time, the calculator automatically calculates the duration across midnight.
How do decimal hours work for timesheets?
Decimal hours divide the remaining minutes by 60. For example, 15 minutes is 0.25 hours, 30 minutes is 0.5 hours, and 45 minutes is 0.75 hours.