This calculator adds or subtracts hours, minutes, and seconds for schedules, timesheets, workouts, and other clock-based arithmetic.
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Enter the starting time or duration, choose addition or subtraction, then enter the hours, minutes, and seconds to apply. Check whether the result crosses midnight or spans more than one day.
Each time is converted to seconds using total seconds = hours × 3600 + minutes × 60 + seconds. The calculator adds or subtracts those totals, then converts the result back into hours, minutes, and seconds.
Start with 2 hours, 45 minutes, and 30 seconds, then add 1 hour, 35 minutes, and 50 seconds. The result is 4 hours, 21 minutes, and 20 seconds after carrying 80 seconds into 1 minute and 20 seconds.
Every 60 minutes is carried into one additional hour. The same rule turns every 60 seconds into one minute.
Yes, if you subtract a larger duration from a smaller one. A negative result means the difference extends backward by that amount.
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