Why convert seconds to H:M:S?
Audio editors, video producers, game developers, and data engineers all work with durations stored as integers — total seconds or milliseconds. Converting 3661 seconds to "1:01:01" manually involves dividing by 3600, 60, and taking remainders — easy to get wrong when tired. This tool handles both directions: seconds to multiple H:M:S formats, and individual hours/minutes/seconds back to total seconds. It also produces decimal minutes and hours, which are useful for spreadsheets and billing systems that expect fractional hours.
How to use this tool
- 1 In Seconds → H:M:S mode, type a number of seconds — six output formats appear: H:MM:SS, zero-padded HH:MM:SS, human-readable, decimal minutes, and decimal hours.
- 2 Switch to H:M:S → Seconds mode and enter hours, minutes and seconds individually.
- 3 The output shows total seconds, total minutes, total hours, and a human-readable duration.
- 4 Click any copy button to grab a specific format.
Frequently asked questions
What is the difference between H:MM:SS and HH:MM:SS?
H:MM:SS omits leading zeros on the hours — 1:05:09 for 3909 seconds. HH:MM:SS always zero-pads to two digits — 01:05:09. Use HH:MM:SS when displaying in a fixed-width column; H:MM:SS for casual display.
What does the human-readable format look like?
Human-readable breaks the duration into natural language parts: "1h 1m 1s". Components that are zero are omitted: 65 seconds becomes "1m 5s", not "0h 1m 5s".
Can I enter fractional seconds?
Yes — decimal seconds like 3661.5 are accepted. The H:M:S formats floor to whole seconds; the decimal outputs preserve the fractional part.
What is a decimal hours value used for?
Billing systems, time-tracking software, and spreadsheets often store durations as decimal hours: 1.5 hours instead of 1 hour 30 minutes. The decimal hours output gives you this value ready to paste.
Is my data sent anywhere?
No. All conversion runs locally using basic arithmetic in your browser.