calculator
Time Duration Calculator ⏱️
Calculate the exact duration between two times, or add and subtract hours, minutes, and seconds from any time. Perfect for timesheets, workouts, and scheduling.
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Operation
Enter a duration to convert
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Hours
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Minutes
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Seconds
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Milliseconds
Total Minutes
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Total Seconds
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📋 How To Use
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Choose a mode. Select Time Difference to find how long between two clock times, Add/Subtract to offset a time by hours/minutes/seconds, or Convert Duration to break a duration into all units.
2
Time Difference mode: Enter your start and end times using the time pickers. If your time range crosses midnight (e.g. 11 PM to 6 AM), select “Yes — crosses midnight” from the dropdown.
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Add/Subtract mode: Enter a base time, choose Add or Subtract, then enter how many hours, minutes, and seconds to offset. Useful for scheduling and time zone adjustments.
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Convert mode: Type any duration in hours, minutes, and seconds. See it instantly converted to total minutes, total seconds, and milliseconds — live as you type.
⚙️ How It Works
Time Difference
Both times are converted to total seconds since midnight. The difference is computed and then converted back to hours, minutes, and seconds. The overnight flag adds 86,400 seconds (24 hours) when the end time is earlier than the start time.
Add / Subtract
The base time is converted to seconds, the offset is added or subtracted, and the result is converted back to a 24-hour clock time. The result wraps correctly around midnight in both directions.
Duration Conversion
Any duration entered in hours/minutes/seconds is normalized — for example, 90 minutes becomes 1h 30m automatically. All equivalent units are shown simultaneously for easy reference.
Common Uses
Timesheets and payroll, workout and training logs, cooking and recipe timing, travel and flight duration, meeting scheduling, shift planning, and sports timing.
❓ Frequently Asked Questions
Use the Time Difference mode. Enter your clock-in time as the start time and clock-out time as the end time. If you worked through midnight, toggle the overnight option. The result shows your total hours and minutes worked. For lunch breaks, calculate the break duration separately and subtract it from your total work time.
This calculator handles time within a single 24-hour period (with overnight option). For durations spanning multiple full days, use our Date Difference Calculator which accounts for full days, then add the remaining hours using the Time Duration Calculator for a complete multi-day duration.
Use the Convert Duration mode. Enter your minutes in the Minutes field and leave Hours and Seconds at zero. The calculator will automatically convert it to hours and minutes. For example, 150 minutes becomes 2 hours 30 minutes. Alternatively, divide the minutes by 60 — the whole number is hours, and the remainder is minutes.
When your start time is later in the day than your end time (for example, starting at 11:00 PM and ending at 6:00 AM the next morning), the overnight toggle adds 24 hours to the calculation. Without it, the calculator would see the end time as earlier than the start time and return a negative result. Always use this option for night shifts or any duration that crosses midnight.
There are 3,600 seconds in one hour (60 seconds × 60 minutes). There are 86,400 seconds in one full day (3,600 × 24). The Convert Duration mode shows all these values simultaneously — enter 1 hour and 0 minutes to see 3,600 seconds confirmed instantly.
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