Free tools for your next audio edit
Convert stereo to mono. Choose the sound you want to keep.
Make a mono WAV or MP3 from a supported short stereo recording. Preview the averaged left and right channels, compare either side, and download locally without an account or audio upload.
Try a 3-second stereo sample first:
Original synthesized tones, not AI results. Nothing plays automatically.
Your audio is read locally; this tool does not upload it. Export is 48 kHz mono: 16-bit PCM WAV, or MP3 at the selected bitrate. Original tags are not copied; neither format restores detail lost in the source. Channel extraction keeps existing audio; it does not separate voices or instruments mixed on the same channel.
Open, compare, save
How to convert stereo to mono
- 01 / OPEN
Choose a stereo file
Open a supported two-channel MP3 or WAV up to 50 MiB and five minutes, or choose a synthetic sample. Your browser reads and processes it locally.
- 02 / PREPARE
Preview the mono mix
Mono mix is selected by default. Choose WAV or MP3, prepare the file and compare the preview with the original. If a wanted sound becomes quieter or disappears, try an individual channel.
- 03 / SAVE
Download the result
Save the same mono file you previewed. The WAV is 48 kHz 16-bit PCM; MP3 is a new lossy encode and may add delay or padding. Keep the original stereo file.
Know what the mix changes
What happens when stereo becomes mono?
This converter averages each pair of decoded samples: (left + right) / 2. Identical signals retain their sample amplitude; a signal on only one side is halved; equal opposing signals cancel. The Web Audio specification describes this stereo-to-mono downmix rule.
Use the built-in Matching channels, Left sound, right silence and Opposite polarity samples to hear these differences. Whole-clip RMS readings provide a comparison, but cannot prove that a brief word or instrument survived. Listen to the important passages. The converter does not correct polarity, align microphones, normalize, or preserve stereo placement.
When the two channels are separate microphones, download each side using the channel splitter and edit them independently. Choosing one side keeps everything recorded there, including any spill. For mixed voices or instruments, use a source separation workflow; averaging channels is not source isolation.
Browser decoding may resample the source to 48 kHz. WAV samples outside the PCM range clip, and the output does not retain original tags or compressed bytes. Longer, multichannel or differently specified exports need a suitable editor.
MP3 encoder credits
Built with the LAME encoder via lamejs.
The optional MP3 download uses lamejs 1.2.1 by Alex Zhukov, a JavaScript port of the LAME MP3 encoder. Its unmodified script is served separately. See the attribution and source notes, upstream license notice, LGPL-3.0 and GPL-3.0 texts, and complete upstream source package.
A few useful answers
Free stereo to mono converter questions
How do I convert stereo to mono?
Choose a stereo MP3 or WAV up to 50 MiB and five minutes. Mono mix is selected by default: prepare, preview and download the WAV or MP3. You can select one channel instead if averaging loses wanted sound.
Does converting stereo to mono upload my audio?
No. Your browser decodes and processes the selected file locally. Conversion, preview and download are free without an account. Save the result before leaving the page.
Why does mono sound quieter or different?
The mix averages corresponding left and right samples. A signal present on only one side is halved; opposing signals can cancel. Compare both individual channels and the averaged preview. This tool does not automatically normalize, align or correct phase.
Can I choose just the left or right channel?
Yes. After opening a stereo file, choose Left channel or Right channel instead of Mono mix. This keeps all sounds on that side; it does not isolate an individual speaker or instrument.
What file formats are supported?
Input must be a supported stereo MP3 or WAV, at most 50 MiB and five minutes. Browser codec support varies. Output is a one-channel 48 kHz 16-bit PCM WAV or a newly encoded 128, 192 or 320 kbps MP3. Tags are not copied.
Will this restore stereo width later?
No. A mono file has one channel and does not preserve the original left-to-right placement. Keep the stereo source if you may need its positioning later.
After preparing your audio