Time Duration Calculator
Calculate the exact duration between two clock times with break deductions and overnight shift support. Whether logging billable contractor hours, calculating employee timesheets, tracking fitness intervals, or scheduling events, this tool computes decimal and standard hours instantly.
Starting clock time (24-hour format e.g. 08:30 or 14:15)
Ending clock time (crossing midnight is automatically handled)
Lunch or pause time subtracted from gross shift duration
Billable or payable decimal hours (e.g. 7.75 hrs)
How to Use This Calculator
- Enter your shift or task starting time in 24-hour notation (e.g., 08:30 for 8:30 AM).
- Enter your shift ending time (e.g., 17:00 for 5:00 PM or 02:00 for overnight 2:00 AM).
- Input any unpaid lunch or rest pause minutes.
- View billable decimal hours for invoicing alongside standard formatted hours and minutes.
Formula & Calculation Methodology
Converts clock strings into total elapsed seconds from midnight. If the end time is numerically smaller than the start time, 24 hours (86,400 seconds) is added to account for overnight shifts before subtracting break intervals.
Worked Example
A shift starting at 08:30 and finishing at 17:00 with a 45-minute lunch break
Frequently Asked Questions
How does the calculator handle night shifts that cross midnight?↓
If your end time is earlier than your start time (such as 22:00 to 06:00), the calculator automatically recognizes an overnight schedule and adds 24 hours to deliver exact overnight hours.
Why are decimal hours important for timesheets and payroll?↓
Payroll software multiplies hourly wage by decimal hours rather than minutes. For example, 7 hours and 45 minutes equals 7.75 decimal hours (45 ÷ 60 = 0.75).
Can I calculate durations under 1 hour?↓
Yes. Entering a start time of 10:00 and end time of 10:45 yields 0.75 hours and 45 minutes.
What limitation applies if a shift spans multiple 24-hour cycles?↓
This calculator models single shifts spanning up to 24 continuous hours. For multi-day projects spanning across several calendar dates, use the Date Difference Calculator.
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Open calculator →Source Citation & Disclaimer
Informational tool only; not licensed tax, legal, or financial advice.