Stereo to mono converter online — free
Quick answer Collapse left and right into one mono channel.
Collapse stereo to a single mono channel — smaller files, simpler voiceovers. 15MB max (Pro: 20MB).
Free to try · No signup required · Commercial use allowed · How we test · About VoxCraft
Convert stereo to mono online for free with VoxCraft. Upload a stereo MP3, WAV or recording, tap Convert to mono, and download a single-channel file — no install and no signup on the free tier.
The left and right channels are mixed together into one. That's what you want for speech: a voice-over recorded on one side of a stereo file, a podcast that should sound the same in either earbud, or a platform that asks for mono audio. It also fixes the common problem of a recording that only plays in one ear — the mixed file plays centred in both.
Mono files are also smaller: with a single channel to store, the result is typically about half the size of the stereo original. If your main goal is a smaller file and you don't need mono, Compress is the other option.
Mono loses the left/right placement that stereo music relies on, so it is better suited to voice than to music you want to keep wide.
How it works
- Upload your stereo file (MP3, WAV, OGG, M4A or FLAC — 15MB max, 20MB with Pro).
- Choose the output format: MP3 or WAV.
- Tap Convert to mono.
- Download the single-channel file.
Who uses this
Voice-overs
Combine a dual-channel or one-sided recording into a clean centred mono track.
Podcasts
Deliver speech that sounds the same on every speaker or earbud.
One-ear recordings
Fix a recording where the voice only plays in the left or right channel.
Platform requirements
Meet an upload or tool requirement for mono audio.
Tips for better results
- If a recording plays in only one ear, converting to mono mixes both sides so it plays in both.
- A channel that's silent still halves the level of the active channel when mixed, so use Normalize afterwards if it sounds quieter.
- Don't convert music to mono unless you need to — you'll lose the stereo width.
- Keep your original stereo file; you can't recreate real stereo from a mono copy.
Frequently asked questions
How do I convert a stereo MP3 to mono?
Upload the MP3, pick MP3 as the output format and tap Convert to mono. You get a single-channel MP3 back.
Is quality lost?
The two channels are combined into one, so stereo placement is lost. For speech that's usually unnoticeable.
Will the file be smaller?
Yes — roughly half the size of the stereo original, since only one channel is stored.
Why is my mono file quieter?
Mixing channels can lower the level, especially if one side was quiet. Normalize it afterwards.
Can I turn mono back into stereo?
Not into true stereo — a mono file has no left/right information to recover.