How it works
- Drop your audio file. MP3, WAV, FLAC, AIFF, OGG or M4A up to 500 MB — its channel layout is detected locally, nothing is uploaded.
- Pick an operation. Stereo → mono downmix, mono → stereo, extract the left or right channel, or swap left and right.
- Download the result. The converted file is exported in the same format as your source: lossless stays lossless, lossy is re-encoded at high quality.
Features
- Five channel operations. Downmix to mono (50/50 mix), duplicate mono to stereo, extract left, extract right, or swap L/R.
- Channel layout detected automatically. The tool reads your file's channels and only offers the operations that make sense for it.
- Same-format export. Lossless sources stay lossless (WAV, AIFF, FLAC); lossy sources are re-encoded at high quality.
- 100% in your browser. Your track never leaves your computer — the conversion runs locally with ffmpeg.wasm.
FAQ
Is this mono / stereo converter free?
Yes. Anonymous users get 5 free uses per day across AudioKit's free tools — no account needed. A use is only counted when you run an operation; loading a file and previewing is free. AudioKit Premium removes the daily limit.
Is my audio file uploaded to a server?
No. The file is decoded, converted and re-encoded entirely in your browser with ffmpeg.wasm and never leaves your machine. The only network call is a tiny anonymous counter that tracks your daily free quota.
Which audio formats are supported?
MP3, WAV, FLAC, AIFF, OGG and M4A files up to 500 MB. The result is exported in the same format as the source: lossless stays lossless, lossy formats are re-encoded at high quality.
Why should I check mono compatibility?
Because a lot of playback is mono in practice: club PA systems, phone speakers, many Bluetooth speakers, and radio can sum your channels into one. If parts of your stereo mix are out of phase, they cancel in that sum — a synth or reverb can simply vanish. Downmixing to mono here is the quickest way to hear what actually survives; the Phase invert and Mix Check tools help you dig into the cause.
Does converting mono to stereo make it sound wider?
Honestly: no. Mono → stereo duplicates the same signal on both sides — the file becomes 2-channel, but both channels are identical, so it sounds exactly the same. Real stereo width comes from differences between the channels (doubling, stereo reverb or chorus, panning), which is a creative step in your DAW, not a conversion.