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Time

HH:MM:SS to Seconds Converter

Aggregating lap times, shift lengths, or media durations sometimes requires a single seconds total for spreadsheets or APIs.

Inputs

Enter your values below. Results update when you calculate.

About HH:MM:SS → Seconds

Aggregating lap times, shift lengths, or media durations sometimes requires a single seconds total for spreadsheets or APIs.

Multiply hours and minutes appropriately and sum with seconds.

Input is clock components; output is total seconds.

How to use this tool

Enter hours, minutes, and seconds. Calculate for total seconds.

Formula & methodology

This hh:mm:ss to seconds converter applies the standard relationship below. Intermediate values are kept at full precision; only the displayed result is rounded.

total s = h x 3600 + m x 60 + s

Tips for accurate results

  • Ensure minutes and seconds stay within 0–59 unless form allows overflow.
  • Use seconds-to-hms to format back.
  • Timezone offsets are separate from duration math.
  • Leap seconds rarely affect everyday duration totals.

Frequently asked questions

1:30:00 in seconds?

5400 seconds.

Omit hours?

Enter 0 hours if only minutes and seconds matter.

Free?

Yes.

Decimal seconds?

Depends on form support for fractional seconds.

Further reading

Guides that explain the ideas behind this calculator.

All guides →
Health 4 min read Sleep cycles: is 6 hours better than 7? What the 90-minute rule actually says The 90-minute rule is a useful planning tool, not a law of nature. What sleep cycles are, where the rule helps, and where it is misused to justify short sleep.

Related tools

More calculators in Time.

Time Seconds → HH:MM:SS Total seconds into hours:minutes:seconds. Time Hours → Minutes Convert hours to minutes. Time Minutes → Hours Convert minutes to hours. Time Days → Hours Convert days to hours.