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Time

HH:MM:SS to Seconds Converter (Time to Seconds)

Convert HH:MM:SS into total seconds instantly with this free time converter. Enter hours, minutes, and seconds to get one number for timers, video editors, APIs, and spreadsheets.

Inputs

Enter your values below. Results update when you calculate.

About HH:MM:SS → Seconds

Convert HH:MM:SS into total seconds instantly with this free time converter. Enter hours, minutes, and seconds to get one number for timers, video editors, APIs, and spreadsheets.

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 (time to seconds) 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.