Normalize audio
Measured first, then brought to an even level — without clipping.
Drop files here
or click to choose from your deviceAccepted: MP3, M4A, AAC, WAV, OGG, OGA, OPUS, FLAC, WEBA
Up to 3 files per runUp to 150 MB per file5 runs per dayRemove limits with Pro✓ Works offline
Your files stay on your device
This tool runs entirely in your browser. Nothing is uploaded, nothing is stored, and you can even turn off your internet connection before you start.
Example
Example: three interview clips recorded at different levels, brought to one
Three clips for a podcast: one recorded far from the phone, one at a normal distance, one too close. Add all three with Volume on Automatic; each is measured on its own.
- Loudness is the average level of the parts with sound in them: pauses and room hiss are left out of the average.
- The gain is whatever brings that to −16 dB, at most +24 dB and at least −12 dB.
- While the quiet clip is raised, every peak is held under −1 dBFS by the limiter, so it does not crackle.
| Clip | Loudness measured | Gain applied | After |
|---|---|---|---|
| Far from the microphone | −31.8 dB | +15.8 dB | −16.0 dB |
| Normal distance | −17.8 dB | +1.8 dB | −16.0 dB |
| Too close | −9.8 dB | −6.2 dB | −16.0 dB |
All three come out at −16 dB and sit at one level in a playlist, named after the originals with -volume (interview-1-volume.mp3). A clip quieter than −40 dB can only be raised by 24 dB, so it ends up a little below the others.
How it works
- Add the recording — one file or several.
- Leave the volume on automatic: the loudness is measured and the gain worked out from it.
- Choose the format to save as, or keep the one you had.
- Download. Files done in one run each get their own level, so a set ends up even.
Frequently asked questions
- What does “automatic” actually do?
- It measures how loud the recording is where there is sound in it, then applies the gain that brings that to a normal level — about −16 dB — and holds every peak under the ceiling on the way, so raising a quiet recording does not make it crackle.
- Can I use it on a set of files so they match?
- Yes. Add them all at once: each is measured on its own and brought to the same target, which is what makes a playlist or a set of interview clips sit at one level.
- Will it fix a recording that is already distorted?
- No. Clipping happened when it was recorded and the peaks are gone; making it quieter afterwards does not bring them back.
- Is it peak or loudness normalization?
- Loudness. The level is measured over the parts with sound in them, with a gate like EBU R128’s that drops pauses (without its frequency weighting), and brought to about −16 dB. Peaks are not the target: they are only held under −1 dBFS, so one loud bang does not keep the rest quiet.
- Can I raise it by a set amount instead?
- Yes: choose +3, +6, +10 or +15 dB, or −6 dB to make it quieter. The same limiter holds the peaks under −1 dBFS, so +15 dB on a song that is already loud mostly squeezes its peaks rather than adding level.
- Is the audio uploaded?
- No. It is decoded, measured and re-encoded in your browser.