Split a Stereo File Into Two Mono Files

How to Split a Stereo File Into Two Mono Files

  1. 1

    Choose the output format

    WAV keeps the split lossless, which is usually the point of pulling a recording apart to edit it. MP3 is there when the two halves are going somewhere that needs a small file.

  2. 2

    Add your files

    Drop in one stereo file or a whole batch. Each row shows how many channels the file turned out to have once it has been read.

  3. 3

    Split

    Press Split. Each stereo file produces two mono files, named after the original with -left and -right on the end.

  4. 4

    Download

    Download each channel on its own, or take the whole batch at once. Files that were already mono are marked as such and left alone.

What this is

A stereo file is two mono signals travelling together, and often they were never meant to be heard as one picture: two lavalier mics printed to the two sides, an interview with the guest on the left and the room on the right, a board feed on one channel and a backup on the other. This tool files them separately — left becomes one mono file, right becomes another — so you can edit, level or transcribe each one on its own. It is a copy rather than a conversion: no downmixing, no gain change, no resampling, nothing to undo later. Files with more than two channels come apart the same way, one file per channel. Everything happens on your own machine, so a recording you are not allowed to upload works here too.

How it works

There is no model and no signal processing behind this one, which is the honest thing to say about it. A decoded audio file is already stored as one array of samples per channel, so separating a stereo pair is a matter of copying each of those arrays into its own single-channel file and writing a header around it — the browser's own decoder reads the input, and the samples are passed through untouched. That is why the result is bit-for-bit identical to the source channel and why it is instant even on a long recording. The one decision the tool makes for you is naming: two channels are labelled left and right, while anything wider is numbered ch1 upwards rather than guessed at, because the running order of a surround file is a convention of whatever wrote it and a file labelled "Centre" that is not the centre is worse than a file labelled "3".

Supported formats

WAV, MP3, M4A, AAC, OGG and FLAC. Files are decoded by your browser, so anything it can play will work here. Output is one mono file per channel, as WAV or as an MP3 at the bitrate you choose.

Frequently asked questions

Is my audio uploaded anywhere?
+Is my audio uploaded anywhere?
No. Everything runs inside your browser using the Web Audio API, so the file never leaves your device. You can prove it: load the page, turn off your Wi-Fi, and the tool still works.
Does splitting change the audio?
+Does splitting change the audio?
No. Each channel is copied out sample for sample, at the original sample rate and level, so a WAV export is bit-for-bit identical to that channel of the source. Choosing MP3 output re-encodes it, as any MP3 does, which is why WAV is the default here.
What happens to a mono file?
+What happens to a mono file?
It is marked "already mono" and left alone. Splitting it would only produce two identical copies under names claiming one is the left channel and the other the right, which would be a tool inventing work.
Can I split a 5.1 or multichannel file?
+Can I split a 5.1 or multichannel file?
Yes. Any file your browser can decode comes apart into one mono file per channel, numbered ch1 upwards. They are numbered rather than named because the channel order in a surround file depends on whatever wrote it, and a wrong label is worse than a number.
How do I put two mono files back together?
+How do I put two mono files back together?
That is the other direction, and it is not this tool. Merge Audio joins files end to end rather than side by side; interleaving two monos back into a stereo pair is not something Audio Magic does yet.
Can I do this as part of a bigger edit?
+Can I do this as part of a bigger edit?
Yes — Split Stereo is also a block in Chain Tools. Put it in a chain and everything below it runs on each channel separately, so you can split a two-mic recording and then normalize each voice on its own in a single pass.
Does this use AI?
+Does this use AI?
No, and it would be a strange place for it. Separating channels is a copy with a correct answer, not a judgement call. Audio Magic saves the AI for problems that genuinely need it: Whisper for transcription, DeepFilterNet3 for noise removal, and Demucs for pulling vocals out of a mixed track — that last one being the job people sometimes mean when they say "separate audio".
Do I need an account?
+Do I need an account?
No. The free tools work straight away with no sign-up, up to 15 minutes of audio per tool per day. An account is only needed if you subscribe to remove the limit.
Is it free?
+Is it free?
Yes. Every tool on this page is free to use, with a daily limit on total audio processed. There is no watermark and no trial period.

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