A duration for an API
A time of 00:02:30 becomes 150 seconds for a field that wants a number.
Use HH:MM:SS to Seconds
Converts hh:mm:ss to seconds in this tab, with nothing sent anywhere.
Runs entirely on your deviceThe conversion happens in this browser tab. Nothing you type is uploaded, logged or stored, which is worth knowing for anything you would not paste into a search box.
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Browse all general convertersAbout HH:MM:SS to Seconds
Systems and calculations frequently want a duration as a single number of seconds, but you have it as hours, minutes and seconds. Converting HH:MM:SS to seconds collapses a clock-style duration into that count. So 01:01:01 becomes 3661 seconds and 90:00 - ninety minutes - becomes 5400, the figure a script, a rate calculation or an API field expects. Rate and pace sums need a single number, so collapsing a clock time to seconds is the step before dividing a distance by a duration or comparing two lengths. Video-editing timecodes and lap times entered as clock values convert to seconds for any spreadsheet formula that has to add or average them. Treat HH:MM:SS as elapsed duration, not a local time with a date or timezone. For example, 02:15:30 is 2 times 3600 plus 15 times 60 plus 30, giving 8130 seconds. Keeping the hours term prevents a long duration from wrapping at one hour.
Using HH:MM:SS to Seconds
- Type a number of HH:MM:SS. You can paste a value with its unit; the tool reads the number.
- The exact factor is applied and the result is shown as seconds, updating live as you type.
- Copy the answer, or switch to the reverse converter to go from seconds back to HH:MM:SS.
Where hh:mm:ss to seconds helps
Both directions
Need the opposite? The seconds-to-HH:MM:SS converter is linked below and uses the exact inverse factor.
Keep duration and clock time separate
For a duration of 02:15:30, calculate 2 x 3600 + 15 x 60 + 30 = 8130 seconds. This does not identify a date or a time zone. A clock interval that crosses midnight needs the start and end dates before it can be treated as a duration. When importing media timestamps, check whether the final field is seconds or a frame count; HH:MM:SS is not a timecode frame format.
Before you use the result
- The result is rounded for readability, so a value converted and then converted back may differ in the last decimal place. The underlying factor is exact.
- Units in your input are ignored - only the number is read - so make sure the figure you type is really in HH:MM:SS.
Questions about HH:MM:SS to Seconds
What formats are accepted?
HH:MM:SS or MM:SS. So 01:30:00 and 90:00 both work, giving 5400 seconds.
Is my data uploaded?
No. HH:MM:SS to Seconds does the arithmetic in this browser tab; the value is calculated on your device and is not sent to a server.
Related tools
Seconds to HH:MM:SS
Convert seconds to hh:mm:ss instantly in your browser. Exact factor, both directions, nothing uploaded.