Does Stereo to Mono upload my file or text to Tool-You servers?

No. Stereo to Mono runs in this browser tab. Files stay on the device. Limit note: Forces one channel. Output MP3. Does not pick WAV or AAC. Max 100 MB.

Should I use Audio Convert instead of Stereo to Mono?

Use Stereo to Mono when you need Downmix to one channel and export MP3. Use Audio Convert when you need Convert between audio formats. They share a category (Audio) but not the same job.

Stereo to Mono

Downmix to one channel and export MP3.

Sets one audio channel (-ac 1) and writes MP3. Unlike Audio Convert this does not pick WAV or AAC. Unlike Extract Audio the input is already audio, not a movie demux. First run downloads the engine.

What Stereo to Mono does

Sets one audio channel (-ac 1) and writes MP3. Unlike Audio Convert this does not pick WAV or AAC. Unlike Extract Audio the input is already audio, not a movie demux. First run downloads the engine.

Stereo to Mono sits in the Audio group on purpose. It is not Audio Convert (Convert between audio formats.) and not Extract Audio (Pull audio from a video as MP3.). Choose this page when you need Downmix to one channel and export MP3. If you stretch Stereo to Mono into a neighbor’s job, the result will look wrong even though the site chrome looks the same.

How to use Stereo to Mono

Stay on this Stereo to Mono page (/audio/mono-audio). Do not switch to Audio Convert unless you actually want Convert between audio formats..
Add the file type Stereo to Mono accepts. Hint from the path: audio · mono audio. Downmix to one channel and export MP3.
Set only the options that match Stereo to Mono. Neighbor Extract Audio does something else (Pull audio from a video as MP3.). Tool note: Sets one audio channel (-ac 1) and writes MP3. Unlike Audio Convert this does not pick WAV or AAC. Unlike Extract Audio the input is already audio, not a movie demux. First run downloads the engine.
Run Stereo to Mono in this tab. Browser memory still applies: Forces one channel. Output MP3. Does not pick WAV or AAC. Max 100 MB.
Download or copy the result from Stereo to Mono. If it is the wrong job, open Audio Convert instead.

When not to use Stereo to Mono

Skip Stereo to Mono when a neighbor tool matches better — start with Audio Convert or Extract Audio — or when the description already warns the job will fail. In the tool’s own words: Sets one audio channel (-ac 1) and writes MP3. Unlike Audio Convert this does not pick WAV or AAC. Unlike Extract Audio the input is already audio, not a movie demux. First run downloads the engine.

Questions about Stereo to Mono

What does Stereo to Mono do that other Audio pages on this site do not?: Sets one audio channel (-ac 1) and writes MP3. Unlike Audio Convert this does not pick WAV or AAC. Unlike Extract Audio the input is already audio, not a movie demux. First run downloads the engine. Short version: Downmix to one channel and export MP3.
Does Stereo to Mono upload my file or text to Tool-You servers?: No. Stereo to Mono runs in this browser tab. Files stay on the device. Limit note: Forces one channel. Output MP3. Does not pick WAV or AAC. Max 100 MB.
Should I use Audio Convert instead of Stereo to Mono?: Use Stereo to Mono when you need Downmix to one channel and export MP3. Use Audio Convert when you need Convert between audio formats. They share a category (Audio) but not the same job.
What are the limits of Stereo to Mono?: Forces one channel. Output MP3. Does not pick WAV or AAC. Max 100 MB. Also: Sets one audio channel (-ac 1) and writes MP3. Unlike Audio Convert this does not pick WAV or AAC. Unlike Extract Audio the input is already audio, not a movie demux. First run downloads the engine.