Time Duration Calculator
Calculate the exact duration between any two times — perfect for tracking work hours, meetings, exercise sessions, and project time with break deductions and overtime calculation.
How to Use the Time Duration Calculator
- 1
Use the Single Duration tab to calculate the time between a start and end time. Enter your start and end times using the hour minute second and AM/PM dropdowns. The calculator handles times that cross midnight automatically.
- 2
Enter your break duration in minutes to calculate net working time after deducting breaks. For example a 9 AM to 5:30 PM shift with a 30 minute break gives 8 hours of net working time.
- 3
Use the Multiple Time Spans tab to add up several separate time periods. This is ideal for freelancers tracking billable hours across multiple sessions or for calculating total time spent on a project across different work periods.
- 4
Download the free PDF report for your time records. The decimal hours format is particularly useful for payroll calculations and invoicing clients for billable hours.
Example Calculation
Scenario: Start: 9:00 AM | End: 5:30 PM | Break: 30 minutes | Standard Day: 8 hours
- Gross Duration: 8h 30m 0s
- Net Duration: 8h 0m
- Total Minutes: 510
- Decimal Hours (gross): 8.50
- Decimal Hours (net): 8.00
- Overtime: 0h 0m
Frequently Asked Questions
What are decimal hours and why are they used?
Decimal hours express time as a decimal number rather than hours and minutes. For example 8 hours and 30 minutes is 8.50 decimal hours and 7 hours and 45 minutes is 7.75 decimal hours. Decimal hours are used in payroll and invoicing because they are easier to multiply by an hourly rate. To calculate earnings simply multiply decimal hours by your hourly rate. For example 8.50 hours at $25 per hour equals $212.50.
How does the calculator handle times that cross midnight?
If your end time is earlier than your start time the calculator automatically assumes the shift crosses midnight. For example a shift from 10:00 PM to 6:00 AM is calculated as 8 hours rather than showing a negative duration. The result clearly indicates whether the time period crosses midnight so you can verify the calculation is correct for your situation.
How do I calculate my total billable hours for the week?
Use the Multiple Time Spans tab and enter each work session for the day. Add rows for each separate period. The calculator totals all spans and shows the result in both hours and minutes and decimal hours. Repeat for each day and add the daily totals. The decimal hours format makes it easy to multiply by your hourly rate for invoicing.
What is the difference between gross duration and net duration?
Gross duration is the total time from start to end without any deductions. Net duration subtracts your break time from the gross duration. For example if you work from 9 AM to 5:30 PM your gross duration is 8 hours 30 minutes. If you take a 30 minute lunch break your net working duration is 8 hours. Net duration is what you would typically report for payroll purposes.
Disclaimer: This report is generated for informational purposes only. Time duration calculations are based on a 24-hour clock. Overtime calculations are based on the standard work day hours entered and do not account for legal overtime rules which vary by jurisdiction. Always verify time calculations for payroll or legal purposes.