Stereo to Mono Converter Online
Convert stereo audio to mono in your browser. Drop a 2-channel file, get a single-channel mono MP3 — halve the file size, guarantee compatibility with mono-only systems.
Convert Stereo to Mono in 3 Steps
No account. No upload. Just drop your audio and press one button.
Upload the Audio
Drag and drop your stereo or multichannel file onto the tool, or click to browse. Files up to 200 MB — the channel count shows up immediately.
Convert to Mono
Hit Convert to Mono. The tool averages every channel into a single track using (L + R) / 2 — no upload, no wait.
Download the Mono MP3
The mono file is encoded at 192 kbps and saved straight to your device — roughly half the size of the stereo source.
Why Notevibes Stereo to Mono Converter
Simple, honest, and built to respect your files.
Channel Averaging
Pure sample-by-sample math: (L + R) / 2 for stereo, or the average of every channel for multichannel files. Deterministic, lossless downmix logic.
Halved File Size
A mono MP3 stores one channel instead of two, so the output file is roughly half the size of a stereo source at the same bitrate. Great for bandwidth-limited uploads.
Privacy First
Your audio is processed locally in your browser using the Web Audio API. Nothing is uploaded, stored, or tracked — the file never leaves your device.
Any Audio Format
Drop in MP3, WAV, M4A, FLAC, or OGG. Anything your browser can decode via the Web Audio API loads into the converter — up to 200 MB per file.
MP3 Output
The mono result is encoded at 192 kbps and saved straight to your device — no watermark, no ads, no re-encoding step on a server.
Works on Mobile
Convert stereo to mono on your phone or tablet. Runs on iOS and Android in Chrome, Firefox, Safari, and Edge.
Your Audio Stays on Your Device
Every file is processed locally in your browser using the Web Audio API. Nothing is uploaded, stored, or analyzed.
No Upload
File never leaves your device
No Account
Start converting immediately
No Tracking
We never see your audio
When to Downmix Stereo to Mono
Common cases where a single channel is the right choice.
Phone & Radio Broadcast Prep
Prepare audio for mono phone or radio broadcast systems that require a single-channel feed
Voice-Only Podcasts
Shrink voice-only podcast episodes where stereo adds nothing but file size
Legacy Mono Hardware
Deliver audio to older playback equipment that only accepts mono input
Smaller Upload Sizes
Cut upload time in half when pushing voice recordings to slow networks or storage quotas
Walkie-Talkie & Intercom
Feed mono-only walkie-talkie, intercom, or two-way radio systems that reject stereo files
Language Learning Audio
Produce mono tracks for language courses — mono is the standard format for pronunciation clips
Need More Than a Mono Downmix?
The full Notevibes Online Audio Editor lets you trim clips, mix multiple tracks, add fades, clean up podcasts, apply voice EQ, and export to MP3 or WAV — all in your browser.
Open Full Audio EditorRelated Audio Tools
More free browser audio tools from Notevibes — no sign-up, no upload.
Frequently Asked Questions
How do I convert stereo to mono?
Drag and drop your stereo file onto the tool, then press Convert to Mono. The converter averages the left and right channels into a single mono track and downloads it as a 192 kbps MP3. No sign-up, no upload — the whole flow runs in your browser.
How does mono downmix work?
Mono downmix averages the channels of the source file sample-by-sample. For a stereo file, the left and right channels are combined using the formula (L + R) / 2. For multichannel sources (5.1 or 7.1), every channel is averaged into one mono track. This is deterministic DSP — same input always gives the same output.
Will I lose stereo effects?
Yes — mono downmix permanently discards stereo information. All panning, stereo widening, and spatial info is merged into a single channel. Anything panned hard left or right may sound different once the channels are averaged, and reverse-phase tricks that rely on L/R cancellation can partially drop out. This is a one-way transformation.
Will the file size be smaller?
Roughly half, since there is one channel instead of two. A 192 kbps mono MP3 is approximately half the size of a 192 kbps stereo MP3 of the same length — a handy size win for voice recordings, podcasts, and anything where stereo adds no value.
Is it free?
Yes. The Notevibes stereo to mono converter is completely free with no sign-up, no watermark, and no limits on how many files you can convert. Max file size is 200 MB.
Is my file uploaded to a server?
No. The converter runs entirely in your browser using the Web Audio API. Your file never leaves your device — nothing is uploaded, stored, or analyzed.
What if my file is already mono?
The tool shows the channel count as soon as you load the file — 1 channel (mono), 2 channels (stereo), or multichannel. If the file is already mono, the Convert to Mono button is disabled because there is nothing to downmix.
Does it work on mobile?
Yes. It runs on Chrome, Firefox, Safari, and Edge on desktop and mobile. Tap to upload, tap Convert to Mono, and the mono MP3 downloads straight to your device.