Time Duration Calculator
Calculate the exact duration between two times or two dates. Results in hours and minutes, decimal hours, and total minutes.
Calculate the duration between a start and end time
Duration
8h 30m
8.50 decimal hours
Hours : Minutes
8:30
Decimal hours
8.50
Total minutes
510
How to Calculate Time Duration
Calculating time duration manually is straightforward when you follow these steps:
Convert to 24-hour format
Convert both times to 24-hour (military) time. For PM times, add 12 to the hour. 1:00 PM becomes 13:00, 5:30 PM becomes 17:30.
Subtract start from end
Subtract the start time from the end time. If the end time is smaller (overnight), add 24:00 to the end time first.
Handle the minutes
If the end minutes are less than the start minutes, borrow 1 hour (60 minutes) from the hours column and add it to the minutes.
Convert to decimal if needed
Divide the minutes by 60 and add to the hours for decimal format. Example: 8h 30m = 8 + (30/60) = 8.50 hours.
The formula
Duration = End Time - Start Time
Example: Start at 8:15 AM (08:15), end at 4:45 PM (16:45). Duration = 16:45 - 08:15 = 8 hours 30 minutes (8.50 decimal hours).
Common Use Cases
Time duration calculations come up in many everyday business scenarios:
Shift length
Calculate how long an employee worked during their shift, including overnight shifts that cross midnight.
Project hours
Track the total time spent on a project or task for accurate billing and resource planning.
Travel time
Determine travel duration between locations for scheduling meetings or calculating mileage reimbursements.
Meeting duration
Calculate meeting length for calendar blocking, billing clients, or tracking time allocation across your week.
For teams that regularly track shift hours and project time, automatic time tracking eliminates manual calculations entirely.
Converting Time Formats
Quick reference for converting minutes to decimal hours. This is essential for payroll, invoicing, and timesheet calculations.
| Minutes | Decimal Hours | Minutes | Decimal Hours |
|---|---|---|---|
| 5 min | 0.08 | 35 min | 0.58 |
| 10 min | 0.17 | 40 min | 0.67 |
| 15 min | 0.25 | 45 min | 0.75 |
| 20 min | 0.33 | 50 min | 0.83 |
| 25 min | 0.42 | 55 min | 0.92 |
| 30 min | 0.50 | 60 min | 1.00 |
Formula: Decimal Hours = Minutes / 60
Frequently Asked Questions
How do I calculate the time between two times?
Subtract the start time from the end time. For example, from 9:00 AM to 5:30 PM: 5:30 PM is 17:30 in 24-hour time. 17:30 minus 9:00 equals 8 hours and 30 minutes (8.50 decimal hours).
How do I calculate duration for an overnight shift?
For shifts crossing midnight, add 24 hours to the end time before subtracting. For example, 10:00 PM to 6:00 AM: 6:00 (next day) + 24:00 = 30:00. Then 30:00 minus 22:00 = 8 hours. This calculator handles this automatically with the "Crosses midnight" toggle.
What are decimal hours and why do they matter?
Decimal hours express time as a decimal number instead of hours and minutes. For example, 2 hours 15 minutes = 2.25 decimal hours. Payroll systems, billing software, and project management tools typically use decimal hours for easier math and accurate pay calculations.
How do I convert minutes to decimal hours?
Divide the minutes by 60. For example: 15 minutes = 0.25 hours, 30 minutes = 0.50 hours, 45 minutes = 0.75 hours. For less common values like 20 minutes, divide 20 by 60 to get 0.33 hours.
Can I calculate duration across multiple days?
Yes. Use the "Between Two Dates & Times" tab to enter a start date and time plus an end date and time. The calculator shows the total duration in days, hours, and minutes, as well as total hours and total minutes.
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Stop Calculating Time Manually
HiveDesk automatically tracks work hours and generates timesheets for your entire team. $5/user/month, all features included.