Time Duration Calculator
Duration math without the carry-the-one headache: enter two time spans, add or subtract them, and get the exact H:MM:SS result — plus decimal hours for payroll and billing.
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How to use this calculator
Enter two durations in hours, minutes, and seconds, choose add or subtract, and get the exact result instantly. Durations can freely exceed 24 hours, and subtracting a larger time from a smaller one gives a negative result.
Example: 2:45:30 + 1:20:45 = 4:06:15; 5:00:00 − 1:30:00 = 3:30:00.
How it works
Each duration is converted to seconds (hours × 3600 + minutes × 60 + seconds), the two are added or subtracted, and the total is converted back to H:MM:SS. The table also shows total seconds, total minutes, and decimal hours (e.g. 1:30 = 1.5 hours) for payroll and billing.
Frequently asked questions
Can I subtract a larger time from a smaller one?
Yes - the result shows as negative, e.g. -0:30:00.
What is decimal hours?
Hours as a decimal (1:30 = 1.5) - handy for payroll and billing.
Does it handle times over 24 hours?
Yes, durations can exceed 24 hours freely.
How is this different from a time-card calculator?
This does pure duration math; a time card tracks clock-in/out shifts.