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Convert a stereo audio file to mono online

Combine the left and right channels of a stereo audio file into a single mono channel, directly in your browser.

Processed on your device via WebAssembly. Nothing is sent to any server.

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Combine the left and right channels of a stereo audio file into a single mono channel, directly in your browser. Useful both for preparing content for platforms that expect mono and for fixing broken recordings.

Mixes the left and right channels into one. This is especially useful when a recording was accidentally captured with a microphone plugged into only one channel — the 'missing' audio from the empty channel is recovered by merging both channels into one.

Use cases

  • Prepare a podcast or voice memo for a platform that expects mono audio.
  • Shrink a file's size, since one channel weighs about half as much as two.
  • Fix a recording where sound was only captured on the left or right channel.

How it works

  1. 1

    Upload your audio

    Supports MP3, WAV, M4A, FLAC, AAC, OGG and OPUS.

  2. 2

    Click Convert

    Nothing to configure — the result is always mono.

  3. 3

    Download the MP3

    With a single combined channel.

Technical details

Uses ffmpeg.wasm to force the output to a single audio channel (automatic downmix), then re-encodes the result as MP3.

Frequently asked questions

Is information lost when converting to mono?

The spatial separation between channels (the stereo feel) is lost, but the sound content of both channels is preserved, mixed into the single channel.

Does it reduce the file size?

Yes — with half the channels, the resulting file is typically about half the size of the original stereo file at the same bitrate.

Video & Audio