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Video & Audio Tools

Stereo to Mono Converter

Turn stereo audio into mono. Mix both channels so nothing is lost, or keep only the left or right channel when one side has the recording you need. Normalise the level after mixing, and choose dual mono when a player or platform expects two channels with the same content.

  • Files stay on your device
  • No sign-up
  • Free to use

How to use Stereo to Mono

  1. Drop a stereo audio file onto the page.
  2. Choose mix, left only or right only.
  3. Choose normalisation and dual mono.
  4. Convert and download.

Stereo to Mono features

Safe mixing

Averaged channels, no clipping.

Pick a channel

Left or right only.

Normalisation

Consistent level after mixing.

Dual mono

Two identical channels if needed.

Any format

MP3, M4A, WAV, FLAC.

Private

Processed in your browser; nothing is uploaded.

When to use Stereo to Mono

  • Podcasts and voice recordings for mono playback.
  • Smaller files for speech.
  • Fixing recordings with one silent channel.
  • Phone systems and speech recognition that need mono.

Stereo to Mono FAQ

Will mixing to mono lose anything?

Stereo width is lost, but all sound from both channels is kept. Rarely, sounds that are out of phase between the channels can partly cancel.

Why normalise?

Averaging can make the mix quieter than the original; normalisation brings the level back up evenly.

Is a mono file smaller?

For uncompressed WAV, half the size. For MP3 and AAC, the encoder can use the bitrate more efficiently.

What is dual mono?

A stereo file whose two channels are identical – useful where stereo is required but the content is mono.

Why does the first run take longer?

Re-encoding uses FFmpeg compiled to WebAssembly (about 32 MB), which is downloaded once and then cached.

Which formats can I use?

MP3, WAV, M4A/AAC, OGG, Opus, FLAC, WMA and AIFF, and the audio of MP4, MOV, WebM and MKV videos. Save in the original format or as MP3, M4A, WAV or FLAC.

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Why and how to convert to mono

Mono audio uses a single channel, played identically from every speaker. For speech – podcasts, audiobooks, lectures, voice messages – it is often the better choice: the voice is centred on every playback system, files are smaller, and nothing is lost when someone listens with one earbud.

Mixing combines the two channels by averaging them. Averaging rather than adding keeps the level within range, so the mix never clips. Optional normalisation then evens out the level, which makes quiet stereo recordings comfortable to listen to as mono.

Sometimes only one channel is useful: a microphone plugged into one side of a stereo recorder, or an interview where each speaker has their own channel. Keeping only the left or right channel avoids mixing in silence or noise from the other side.

Some platforms and editors expect stereo files. Dual mono provides two identical channels, which sounds exactly like mono everywhere.

For podcasts with two speakers recorded on separate channels, mixing to mono is usually the best choice: both voices end up in the centre at a similar level, which is how most listeners expect a conversation to sound in earbuds and on phone speakers.

The conversion runs in your browser.

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