Mix stereo audio to mono, keep only the left or right channel, or swap the sides
Processed in your browser. Nothing is uploaded. Checked against sources on 16 Oct 2026.Stereo to Mono Converter mixes the two channels of an audio file into one in your browser, by averaging them so the level holds, or keeps only the left or right channel, swaps them, or makes mono stereo. Files up to 300 MB work, nothing is uploaded, and the result is a WAV.
Press Choose an audio file or drop it on the page; it is decoded and each channel measured on your device.
Leave Channels on Mix to mono, or choose Left only, Right only or Swap left and right.
Read the line under the choices: it warns if the channels cancel or one side is silent.
Press Convert channels, compare the players, then press Download.
Most voice recordings gain nothing from two channels, and some are actively broken by them: a lapel microphone recorded onto the left only, a podcast guest heard in one ear, a phone call recorded with sides reversed. Mono also halves the size of an uncompressed file.
Five channel jobs.
| Choice | Result | Channels |
|---|---|---|
| Mix to mono | the average of left and right | 1 |
| Left only | the left channel as it was | 1 |
| Right only | the right channel as it was | 1 |
| Swap left and right | sides exchanged | 2 |
| Mono to stereo | the same sound in both | 2 |
Why an average. Adding the channels would double the level of anything recorded on both and clip it; the average, (L + R) / 2, keeps a centred voice exactly as loud as before. A sound present on one side only drops by 6 dB in the mix, which is why the page suggests keeping that side instead.
Measured before the tap. Each channel's level is shown, and the page warns when both channels are identical (already mono in a stereo file), when one side is silent, or when the mix comes out at least 6 dB quieter than the louder side, the sign of channels that cancel because one is phase-inverted.
Exact. Left only, Right only, Swap and Mono to stereo copy samples unchanged; the tests compare every output sample with the input. The result is a 16-bit WAV at the original sample rate, and nothing is uploaded.
Drop the file on Stereo to Mono Converter, leave Channels on Mix to mono and press Convert channels. Both channels are averaged into one, so the level stays the same and nothing clips. The mono WAV downloads at the original sample rate and is half the size of a stereo WAV.
The sound was recorded onto one channel only, usually because a mono microphone was plugged into a stereo input. Choose Left only or Right only, whichever has the sound, to get a mono file at full level that plays in both ears. The page measures both channels and says which side is silent.
If one channel is the inverse of the other, which happens with a miswired cable or some stereo effects, averaging them makes parts cancel out. The page compares the mix with each channel and warns when it is 6 dB or more quieter; keeping one side avoids the problem.
Choose Swap left and right and press Convert channels. The result is still stereo, with what was on the left now on the right and the other way round, which fixes recordings made with the microphones or cables reversed. Any channels beyond the first two stay where they were.
Yes. When the file has one channel, the page offers Mono to stereo, which puts the same sound in both channels. It does not create a stereo image, which would need separate recordings, but it suits players and editors that expect two channels.
No. The file is decoded and converted by your own browser, and the WAV is written on your device. Nothing is sent to a server, so interviews and voice notes stay private. Files up to 300 MB and three hours long work in a browser tab.
Rates and rules change; check the source before you rely on a figure.
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Same job, other tools: Frequency Generator – Generate a steady test frequency for speakers, headphones or instruments · Sweep Tone Generator – Sweep smoothly between two frequencies over a time you choose · High Frequency Hearing Check – Screen the top tones, 4 kHz and 8 kHz, ear by ear, then test higher with a tone generator · Audio Sweep Generator – Play a slow logarithmic sweep and hear every rattle in the room.
On the related tools: Mic Test – See your voice on a live waveform and hear it played straight back.