How much dead air is in your video?

Pick a video. A few seconds later you will see how much silence is in it and where it sits. No account, no upload — the measuring happens in your browser and the file never leaves your device.

How the measuring works

The audio is sampled in windows of 20 milliseconds and each window gets a level in decibels. What counts as silence is a threshold below that — and the threshold is not fixed. It sits 10 dB under the average level of this particular file. It has to work that way, because phones ride their own gain: a quietly recorded file has a completely different noise floor than a loud one, and one fixed number would be wrong for one of them. The threshold that came out is shown in the result above.

What gets measured is the loudest channel, not the sum of both. Downmixing stereo cancels signal through phase and then reports silence where there is sound — at the same spot that easily adds up to 0.6 seconds. If one channel is loud, it is not a pause.

Only a stretch that stays quiet for longer than one second counts as a pause. A 0.3 second breath carries the rhythm and should stay in.

Why this is not the same number your editor shows

This measurement says where there is no sound. Whether you may cut there is a second question: a final syllable fades below the threshold before the word is actually over. Cut exactly where the measurement says and you clip the "s" off "captions". A real cut therefore gets nudged back to the word boundaries and keeps a little air, so the length actually removed is a bit less than the dead air shown here.

What happens to your file

Nothing. There is no upload and no server call: the audio track is pulled out of the file in your browser, decoded and measured there. Close the tab and it is all gone. That is also why this tool needs no account.