A walkthrough, end to end.
- 1
Enter a start and end time (HH:MM:SS).
- 2
If the end is earlier than the start, 24 hours is added (overnight).
- 3
See total duration in seconds, minutes, and h:mm:ss.
Time difference
Convert each time to seconds since midnight, subtract, and adjust by 24h if negative.
What you can do with this.
Stopwatch results
Compute elapsed time when you forgot to start a timer.
Race times
Difference between race start and finish.
Cooking
Total cook time across multiple steps.
Class duration
Verify lecture or exam length.
Movie length
Duration from start to end timestamps.
Overnight calculations
Handles times that cross midnight.
Music tracks
Compute total play time from start to end.
Time duration 2026 — what's current
Standard arithmetic; calculator wins for instant overnight handling.
Frequently asked.
Yes — if end time is before start, 24 hours is added automatically.
Yes — use HH:MM if you don't need second-level precision.
No. All math runs in your browser.
Compute each, then sum the seconds.