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Convert HH:MM:SS to Seconds

Convert HH:MM:SS timestamps to total seconds, with optional fractional seconds.

Time input (HH:MM:SS)

Enter one or more time values in HH:MM:SS format (one per line) to convert them into the equivalent total number of seconds. You can also enable support for fractional seconds.

Allows `SS.sss` (e.g., 45.5 seconds).

Results

Paste one or more HH:MM:SS values and click Convert.

How to Use This Tool

  1. Paste one or more times in HH:MM:SS format (one per line).
  2. Enable “Support fractional seconds” if needed.
  3. Click Convert to see total seconds for each line.

Learn More About Convert HH:MM:SS to Seconds

Why convert HH:MM:SS to seconds?

Converting to seconds makes it easy to add, subtract, average, and compare durations. It also avoids common base‑60 mistakes (like treating 7 hours 30 minutes as 7.3).

Formula

Total seconds = (hours × 3600) + (minutes × 60) + seconds

Base‑60 Time (Sexagesimal)

Time is measured in base‑60: 60 seconds per minute and 60 minutes per hour. Converting HH:MM:SS into total seconds makes durations easy to sum, compare, and compute in spreadsheets or code.
HH:MM:SS uses a base‑60 system; seconds conversion makes arithmetic easier.
Seconds in a minute
60
Minutes in an hour
60
Seconds in an hour
3600

Examples

Sample Scenario

Runtime-verified example for convert-hh-mm-ss-to-seconds
Input
{"timeInput":"01:10:30\n00:00:59.5","handleFractions":true}
Output
[{"input":"01:10:30","seconds":4230},{"input":"00:00:59.5","seconds":59.5}]

Use Cases

  • Convert video timestamps into seconds for editing or captions.
  • Normalize log durations for analytics and dashboards.
  • Prepare time data for spreadsheets and formulas.
  • Handle fractional timestamps from telemetry (e.g., 12.75 seconds).

Frequently Asked Questions