Why Use a Time Calculator?
Calculating time differences manually is prone to errors, especially when crossing the AM/PM boundary or dealing with overnight shifts. Whether you are a freelancer billing hourly, an HR manager verifying timesheets, or just planning a road trip, accuracy matters.
Our Time Duration Calculator simplifies this process. It handles the complex math of 60-minute hours and 24-hour days, giving you precise results instantly.
Key Features
Smart Shift Logic
Automatically detects overnight shifts (e.g., 10 PM to 6 AM) without needing date inputs.
Payroll Ready
Converts "8 hours 30 minutes" to "8.5 hours" for easy multiplication with hourly rates.
Break Deduction
Enter unpaid break time (e.g., 45 mins) to get the net billable hours instantly.
Date Span Mode
Switch to "Date Mode" to calculate the duration between specific calendar dates and times.
How to Calculate Work Hours
Getting your timesheet right is easy. Follow these steps:
Start & End
Enter the time you clocked in (e.g., 9:00 AM) and the time you clocked out (e.g., 5:00 PM).
Add Breaks
If you took an unpaid lunch, enter the duration in minutes (e.g., 30) in the Break field.
Get Total
The tool displays the total duration (e.g., 7h 30m) and the decimal value (7.5) for payroll.
Understanding Time Math
Payroll Tip: Most accounting software requires time in decimal format. Converting minutes involves dividing by 60. For example, 15 minutes is 0.25 hours, not 0.15 hours.
The Formula
The basic formula for calculating time difference is:
If the End Time is smaller than the Start Time (which happens in overnight shifts), you must add 24 hours (or 1440 minutes) to the End Time before subtracting to get a positive result.
Common Decimal Conversions
- 15 mins0.25 hours
- 30 mins0.50 hours
- 45 mins0.75 hours
- 10 mins0.17 hours