Time Duration Calculator
Add or subtract hours, minutes, and seconds from any time — calculate durations, end times, and time arithmetic.
What Does This Tool Do?
Enter a start time and a duration to add or subtract. Get the result time with overflow/underflow handled correctly (e.g. 23:50 + 30 min = 00:20 next day).
Key Features
Time Arithmetic
Add or subtract hours, minutes, and seconds.
Overflow Handling
Handles midnight crossings correctly.
Duration Display
Shows result in multiple formats.
Instant
Calculates immediately.
How to Use This Tool
- Enter a start time.
- Enter hours, minutes, seconds to add or subtract.
- Choose Add or Subtract.
- See the result time.
How It Works
Converts all time values to seconds, performs the arithmetic, then handles modulo 86400 for midnight overflow/underflow.
Common Use Cases
💡 Scheduling
Calculate end times from start time and duration.
💡 Time Tracking
Add up work hours across multiple tasks.
💡 Travel
Calculate arrival time from departure and flight duration.
Frequently Asked Questions
What happens at midnight?
Times wrap around correctly — adding 2 hours to 23:00 gives 01:00 (next day indicated).
Related Tools
Link to This Tool
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<a href="https://adedx.com/tools/time-duration-calc/">Time Duration Calculator — AdeDX Free Online Tools</a>