AudioAdjustable qualityRuns in your browser

Normalise Audio

Even out loudness across a file using the EBU R128 standard. Some detail is discarded to fit the target format; how much depends on the format and your settings.

Not uploaded to any serverConverted on this deviceGone when you close the tabHow this works

Drop your files here

MP3, WAV, FLAC, AAC and 4 more formats · up to 300 MB each

or paste files from your clipboard

Ready when you are

Even out loudness across a file using the EBU R128 standard. Everything happens in this tab; nothing is sent anywhere.

⌘K to search converters

How to use it

1
Add your files
Normalise Audio works with MP3, WAV, FLAC, AAC, M4A, OGG, Opus and AIFF. Drop them in, browse for them, or paste from your clipboard.
2
Choose your options
Tune bitrate, sample rate and channels — or leave the defaults, which are sensible.
3
Run it and download
Press the button and save the result. Everything happens on your device, and nothing is uploaded.

Privacy, in plain words

Is it safe? Your audio file is not uploaded anywhere

What “uploaded” normally means. On most online converters, pressing the button copies your file across the internet onto a computer owned by that website. That copy is what the word “upload” means, and it is the part nobody explains.

What happens instead. This site does not do it. There is no server here that receives files, so your audio file is read, converted and handed back by the browser you are using right now. It never travels — so there is no copy to store, read, leak or hand over.

Check it yourself in ten seconds

Turn off your Wi-Fi after this page has loaded, then convert a file anyway. It still works, because everything needed is already on your device.

The longer explanation of how this works, and the full detail of what is and is not stored on the privacy page.

Why this matters more than it sounds

An audio file is a conversation. Transcribed by machine — which is cheap now — it becomes searchable text about whoever was speaking. It matters more than it sounds, because of what audio files usually are:

Unreleased music

work whose commercial value depends on control of the master

Call recordings

both sides of a conversation, often legally sensitive

Interviews

a source's voice is identifying even when the name is not said

Voice notes and dictation

thinking out loud, never meant for an audience

A file that is never sent cannot be kept, leaked, subpoenaed or used to train anything. That is a property of how this works, not a promise about how carefully it is run.

Making the loudness consistent

Normalising adjusts the overall level of a recording so it sits at a predictable loudness. The point is not to make things louder but to make several things match — an interview where one speaker was close to the microphone and the other was across the room is the case this exists for.

It changes level, not content. Background hiss is raised along with the voice, and a recording that was distorted when it was captured stays distorted; normalising a clipped file makes the clipping easier to hear rather than repairing it.

Peak versus perceived loudness: Matching the loudest instant of two files does not make them sound equally loud, because loudness is about the whole recording rather than its single highest sample.
Do it before joining: Normalising each part and then merging gives an even result. Normalising after merging just scales the imbalance.

Measured, not estimated

What this tool actually does to a file

Levelling the loudness at the default target.

The result came out 1.5× larger than the file that went in.

Each row is one document, chosen because this tool behaves differently depending on what is inside the file.
Sample	In	Out	Change
An easy clipThe compressible end of the range — a clean tone, or a moving test pattern — where a codec does its best work.	32.3 KB	48.4 KB	+50%
A hard clipThe other end — pink noise, or dense video grain. Close to incompressible by design, and the worst case for every codec.	32.3 KB	48.4 KB	+50%

Produced by this site's own converter. The same code that runs in your browser, at the same default settings, so these are the bytes you would download.

Samples are generated from a fixed seed rather than taken from real photographs or documents, so the corpus is reproducible and carries no licensing question — and so the numbers predict the shape of your result rather than its exact size. Measured 2026-10-01. The method, and the command that regenerates every figure on this page, are on the how it works page.

About these formats

Accepts

MPEG-1 Audio Layer III

The universal lossy audio format.

Extensions: .mp3
MIME type: audio/mpeg
Best for: Music players · Podcasts · Maximum compatibility
Compatibility: Plays absolutely everywhere.

Accepts

Waveform Audio

Uncompressed PCM audio. Perfect quality, big files.

Extensions: .wav, .wave
MIME type: audio/wav
Best for: Editing and mastering · Sound design · Archival
Compatibility: Universal.

Targets -16 LUFS, the usual level for podcasts and streaming.

Good to know

Normalise Audio — questions

How does Normalise Audio work?

Even out loudness across a file using the EBU R128 standard. Add your files above, adjust anything you want to change, and press the button. The result downloads straight to your device.

Is there anything I should watch out for?

Targets -16 LUFS, the usual level for podcasts and streaming.

Is Normalise Audio safe — are my files uploaded to a server?

No, nothing is uploaded. On most online tools, pressing the button copies your file across the internet onto a computer owned by that website, where it is processed and then sent back. That copy is what "upload" means. This tool does not do it: your file is read and processed by the browser you are using right now, stays on this device the whole time, and is discarded when you close the tab. Turn off your Wi-Fi after the page loads and it still works, which is the quickest way to confirm it.

Can I use this on confidential or personal documents?

Yes — that is the case it was built for. Because the file never leaves your device, a confidential document is no more exposed than it is sitting in your own folder: there is no transfer, no copy on anybody else's hardware, no retention period and no staff with access. Nothing about the file is logged either — not its name, not its size, not its contents.