MP3Conv

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Stereo ↔ Mono Converter

Downmix to mono, fan to fake stereo, or extract just the left or right channel.

Operation

About this stereo / mono converter

Channel surgery for any audio file. Convert a stereo recording to a single-channel mono file (smaller, mono-compatible, podcast-friendly), fan a mono recording out to two channels, or pull just the left or right channel from a stereo source.

No upload, no signup, no quality cap on the source file.

How to convert stereo to mono online

  1. 01

    Drop in audio

    MP3, WAV, FLAC, OGG, M4A and other formats are accepted.

  2. 02

    Pick an operation

    Stereo → mono, mono → stereo, or extract left / right.

  3. 03

    Download the result

    The converted file is rendered and offered as a download.

Why use this stereo / mono tool

  • Stereo to mono downmix (sum of both channels)
  • Mono to stereo (duplicates the channel — "fake stereo")
  • Extract left channel only or right channel only
  • Output keeps the same format as the input
  • Free, private, no install
  • No watermark, no signup, no length cap

Stereo / mono FAQ

Why downmix to mono?

Smaller file size, guaranteed compatibility with mono speakers (phones, smart speakers, voicemail systems), and the right format for AES-podcast loudness targets.

What does 'mono to stereo' actually do?

It duplicates the single channel into both left and right. The result is technically stereo but isn't truly wide — there's no room information to recover.

When would I want to extract just one channel?

When you've got a podcast or interview with one speaker on the left and another on the right and you need them isolated.

Will the audio be re-encoded?

Yes — channel changes require re-encoding. The output uses the same format as the input at a sensible quality default.

Pitch, speed, vocals, bass

See all effects tools