Convert Audio to Mono

Pick an audio file — it's downmixed to a single channel in your browser, nothing is uploaded.

Convert audio to mono in your browser

Pick an audio file and it's downmixed to a single channel with ffmpeg, entirely in your browser. mix (the default) blends every channel using ffmpeg's standard downmix — the classic (L+R)/2 for stereo, and the proper weighted fold-down for 5.1/7.1 surround. left or right instead keeps just that side of the recording.

Worked example

A two-person interview was recorded with each voice on its own side, and the right channel picked up an air conditioner. Upload interview.wav, set Channel to left and Format to mp3 — the result interview-mono.mp3 contains only the clean left-side voice track. For normal music or voice memos, leave Channel on mix.

Why go mono?

Voice content (podcasts, dictation, calls) doesn't benefit from stereo, and mono mp3 files are noticeably smaller at the same quality.
Many transcription and telephony systems expect a single channel.
One-sided recordings (mic plugged into one input) become properly audible on both earbuds.

Limits and edge cases

Input files up to 10 MiB; any format ffmpeg can decode works.
left/right reference the first two channels; on a surround source they pick the front-left/front-right channels.
A file that is already mono passes through unchanged (aside from re-encoding).
Output is re-encoded (mp3/ogg at 192 kbps; wav/flac lossless; m4a AAC). Embedded album art is dropped.

FAQ

Does mixing to mono make the audio quieter?

Slightly, when the two sides differ: ffmpeg's downmix averages the channels, so sound present on only one side ends up at half its original level. Sound present on both sides (like most voice recordings) keeps its level. If the result is too quiet, run it through the audio-normalize tool afterwards.

When should I use left or right instead of mix?

When one channel is the only good one: interviews recorded with a single mic panned to one side, damaged tracks with noise on one channel, or hardware that recorded silence on one side. Mixing in a bad channel would add noise — keeping just the good side avoids that.

Can I convert mono back to stereo?

A mono file plays through both speakers already — players duplicate the channel automatically. True stereo (different left/right content) can't be recovered once it's mixed down; keep your original file if you may need the stereo image again.

Is my audio uploaded anywhere?

No. The page downloads an ffmpeg WebAssembly build once and then processes your file locally in the browser tab — the audio never leaves your device.

Developer & Automation Access

Run it from the terminal

Same engine as this page, headless — via the gizza CLI:

gizza tool audio-to-mono 'url=https://example.com/input' 'channel=mix' 'format=mp3'

New to the CLI? Get gizza →

Open it by URL

Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:

https://gizza.ai/tools/audio-to-mono/?url=https://example.com/input&channel=mix&format=mp3