Mono / Stereo and Channel Swap
Three channel operations in one place: fold stereo down to mono, copy mono up to stereo, or swap left and right. Everything happens in your browser.
The conversion engine (about 32 MB) loads once on your first run and starts instantly from cache afterwards.
Which mode you need
Convert to mono sums the two channels into one — it rescues an interview where the lapel mic landed on a single side, and it roughly halves the data. Convert to stereo duplicates a mono track across both channels for gear or software that insists on stereo input. Swap channels fixes a recording that was wired backwards.
Sound only on one side
A microphone recorded into one channel only is a common accident. Converting to mono sums both channels so the audio plays normally in any headphones. If the result feels quiet, follow it with normalization on the volume page.
Effect on file size
Mono carries half the information, so the same perceived quality needs a lower bitrate. Speech-led material is perfectly usable at mono 96 kbps. Music is better left in stereo, since downmixing destroys the stereo image.
Frequently asked questions
Does converting to mono reduce quality?
You lose the stereo image, but clarity is unaffected. Speech recordings are often easier to follow in mono, and the file gets smaller.
Does mono to stereo make the sound wider?
No. The same signal is copied to both channels, so it still sounds mono. It is a format conversion for tools that require two channels.
How do I tell if the channels are swapped?
Wear headphones the right way round and listen for whether sounds arrive on the side you expect. If they do not, use the swap mode.