Time Duration Calculator
Calculate the duration between two times of day.
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Reviewed by
Vikram RaoSenior Software Engineer
About the Time Duration Calculator
Time duration calculation is fundamental to payroll, invoicing, scheduling, and project management. This calculator converts a start and end time into a precise duration in hours, minutes, and seconds — and in decimal hours for direct use in timesheets and billing.
The calculator automatically handles overnight durations: if the end time is earlier than the start time, it assumes the interval crosses midnight and adds 24 hours accordingly. A night shift from 22:00 to 06:00 is correctly calculated as 8 hours, not −16 hours.
Decimal Hours Quick Reference
| Hours : Minutes | Decimal Hours | Calculation |
|---|---|---|
| 1:15 | 1.25 | 15 ÷ 60 = 0.25 |
| 1:30 | 1.50 | 30 ÷ 60 = 0.50 |
| 1:45 | 1.75 | 45 ÷ 60 = 0.75 |
| 7:30 | 7.50 | 30 ÷ 60 = 0.50 |
| 8:20 | 8.33 | 20 ÷ 60 = 0.333… |
| 10:00 | 10.00 | Full hours, no fraction |
Common Use Cases
Timesheets & payroll
Calculate exact hours worked per shift. Multiply decimal hours by your hourly rate to get billable or payable amounts without manual arithmetic.
Freelance invoicing
Track time spent on client work. Convert hours:minutes to decimal hours and multiply by your rate. 3 hours 20 minutes at $75/hr = 3.33 × $75 = $250.
Meeting & event duration
Quickly calculate how long a meeting, webinar, or live event ran from its start and end times for records, reporting, or billing.
Night & rotating shifts
Calculate overnight shift durations without manual midnight-crossing math. Enter clock-in and clock-out times and get the exact hours worked.