Calculate Seconds Since Midnight

The integer count of whole seconds elapsed from 00:00:00 local time to the given time. 01:00:00 is 3,600 seconds, 12:00:00 is 43,200, and 23:59:59 is 86,399 – one short of the 86,400 total seconds in a day.

It’s the canonical “time of day as an integer” for logging, scheduling, sorting events within a day, populating database columns that store time-of-day only, and quick arithmetic on durations inside a single day.

Straight multiplication: seconds = hours × 3,600 + minutes × 60 + seconds. For 02:30:45 that’s 2×3600 + 30×60 + 45 = 9,045 seconds.

86,399 – exactly one second before the next midnight at 23:59:59. Adding one more second wraps back to 00:00:00 on the following day.

Current-time mode uses your device’s local time zone via new Date(). Custom-time mode treats the input as a zone-agnostic time-of-day – the math is the same regardless of UTC offset.

The tool always returns seconds for the wall-clock hour/minute/second it reads. On DST “spring forward” or “fall back” days, two wall-clock times can map to the same integer because the tool is not aware of the UTC offset shift – which is the standard behavior you want for log sorting by time-of-day.

Your current seconds divided by 86,400, expressed as a percentage. 00:00:00 = 0%, noon = 50.0000%, 18:00:00 = 75.0000%, 23:59:59 = 99.9988%. Useful for progress-bar widgets that show how far into the day you are.

Yes. Once the page has loaded, every calculation runs locally in your browser. Disconnect from the network and the tool keeps working.

Yes on both counts. It runs 100% client-side – no server call, no analytics on the times you enter – and it’s free with no sign-up or usage caps.

Yes. Copy puts the raw integer on your clipboard so you can paste directly into Python, SQL, or JavaScript. The stats line also gives you the “seconds until midnight” which is handy for countdown timers.