Stereo to Mono
Stereo to Mono converts audio to one channel in your browser, mixing left and right or keeping one side, and detects a silent channel or a file that is already mono.
At a glance
- Accepts
- MP3, M4A, AAC, WAV, FLAC, OGG and Opus audio, or the sound in a video file
- Outputs
- MP3 (192 kbps), WAV (16-bit) or M4A when the browser has an AAC encoder; the sample rate is kept where the format allows
- Where it runs
- Entirely in your browser, on your device
- What leaves your device
- Nothing - the file never leaves your device
- Limits
- A channel under -60 dBFS counts as silent; mixing real stereo music can thin it out
- Account
- Not required - there is no sign-up
- Price
- Free, with no watermark and no usage cap
- Made by
- Visrut
- Last updated
- 13 October 2026
Turn a stereo file into a single mono channel. It measures both sides first and tells you what it found: a dead channel (the usual cause of audio stuck in one ear), two identical channels, or real stereo. Then mix the two together, or keep just the side that has the sound.
How to use it
- Drop in an audio or video file.
- Read what it found about the channels; the best option is picked for you.
- Press Make mono and download the result.
Honest limits
- A channel counts as silent when its peaks stay under -60 dBFS.
- Mixing stereo music to mono can make some parts sound thinner, when left and right partly cancel out. That is a property of the recording, not the tool.
- Everything runs in your browser tab; the file is never uploaded.
- Long files are read and processed a piece at a time, so the length of the recording isn't the limit. The finished file is held in memory until you save it: about 86 MB per hour as MP3, and about 690 MB per hour of 48 kHz stereo as WAV, which a phone may not manage.
- MP3 and M4A are re-encoded at 192 kbps, which is a lossy step (like any edit to an MP3). WAV is uncompressed 16-bit.
- M4A is offered only when the browser has an AAC encoder (most desktop Chrome, Edge and Safari do; Firefox does not).
Frequently asked questions
My recording only plays in one ear. Will this fix it?
Yes - that usually means one channel is silent, which is common with a single microphone plugged into a stereo input. The tool detects it and picks 'Keeping left only' or 'Keeping right only', so the sound plays from both speakers at full volume.
Why not just mix both channels?
Mixing averages left and right. When one of them is silent, the average is half as loud (6 dB quieter). When both carry sound, mixing is the right choice.
How do I know if my file is already mono?
The tool tells you: a file with one channel is mono, and a stereo file whose left and right are identical is mono in all but name. Converting the second kind changes nothing you can hear.
Why convert to mono at all?
Some places want mono (many phone systems and voice apps), it fixes one-sided recordings, and a mono WAV is half the size.
Is my audio uploaded?
No. The channels are mixed inside your browser tab.