Time & Date
Time Duration Calculator
Use this duration calculator to combine time spans for homework, projects, workouts, videos, or schedules.
Duration
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- Total seconds
- —
- Total hours
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Student quick launch
Grade planning, algebra checks, and formulas students reach for most.
Study path
Use this calculator with
Follow these when you want the formula behind the answer, a short lesson, or nearby tools in the same topic.
What the time duration calculator solves
Use this duration calculator to combine time spans for homework, projects, workouts, videos, or schedules.
Formula
How to use it
- Choose add or subtract.
- Enter the two durations.
- Read the normalized days, hours, minutes, and seconds.
How to read the answer
The normalized answer carries extra seconds into minutes, minutes into hours, and hours into days.
Common mistakes and edge cases
- Minutes and seconds can exceed 59; the calculator normalizes them.
- Subtracting can produce a negative duration.
- Use elapsed-time calculators for clock start/end times.
Worked examples
Add durations
Duration
1d 6h 15m 15s
Subtract durations
Duration
0d 3h 15m 0s
Frequently asked questions
Can I enter more than 60 minutes?+
Yes. The calculator converts extra minutes into hours.
What is total hours used for?+
Total hours is useful for billing, time tracking, and comparing durations as a decimal.
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Last updated: May 8, 2026