Mono ↔ Stereo Converter
Convert between mono and stereo: fold a stereo file to a single channel, or spread a mono recording across two.
Convert with this tool
or choose a file from your device — it is processed in this tab and never uploaded
Accepted: WAV, MP3, FLAC, M4A/AAC, OGG, Opus
Files stay on your device. There is no upload, no queue and no watermark, so a conversion works even with the network switched off after the page has loaded.
Supported formats & processing
| Accepted input | WAV, MP3, FLAC, M4A/AAC, OGG, Opus |
|---|---|
| Produced output | MP3, WAV, FLAC or M4A with the chosen channel layout |
| Processing | Web Audio API + canvas + native JavaScript encoders |
| Upload required | No — the file is read locally and never transmitted |
How to use this tool
- Add the fileThe source channel count is reported from the decoded buffer.
- Choose the target layoutMono for speech and file-size savings, stereo for compatibility and editing.
- Pick an output formatWAV for editing, MP3 or M4A for distribution.
- ConvertChannel mapping happens during the offline render.
- Confirm in the result cardThe output channel count and bitrate are shown next to the source values.
About this tool
Mono means one channel of audio. Stereo means two, usually carrying slightly different signals to create a sense of space. Choosing the wrong one wastes space or loses information — and both mistakes are easy to make.
Converting stereo to mono halves the raw data, which matters for spoken-word content where the two channels are usually near-identical. Converting mono to stereo is mostly a compatibility move: some players and editors expect two channels, and this tool creates them properly with the correct channel count in the codec header rather than duplicating bytes by accident.
Features
- Genuine channel remapping, not a header edit
- Halves the data rate when folding stereo down to mono
- Correct channel count written into every output codec
- Reports source and output channel layouts side by side
- Works with every format the browser can decode
- Useful for podcast pipelines and voice-model training sets
Frequently asked questions
Will mono conversion lose my stereo effects?
It will. Anything panned hard left or right is summed, and phase differences between the channels can cause cancellation. For music with wide stereo imaging, keep stereo.
Does converting mono to stereo create a stereo effect?
No. Both channels carry identical audio, which is what compatibility requires. If you need a genuine sense of width, that is a mixing decision, not a format conversion.
How much smaller is mono?
The raw data halves. In a lossy format the saving is usually a little less than half because the bitrate per channel does not scale perfectly linearly.
Why does my mono file sound different from the stereo original?
Summing two channels can raise the level by up to 6 dB and can cause partial cancellation where the channels are out of phase. Compare the peak figures in the result card.