File Converter

WebM to M4A converter Free, private, no upload.

Convert WebM files to M4A right in your browser. M4A is the native audio format for iPhone, iTunes and Apple Music, with good quality at small sizes. Your files are never uploaded.

or drop files anywhere · paste with Ctrl/⌘ + V

How to convert WebM to M4A

  1. 1 Drop your WebM files onto the page, or click “Choose files”. You can add many at once, or a whole folder.
  2. 2 M4A is already selected as the output. Optionally open Options to adjust bitrate, sample rate, channels.
  3. 3 Click Convert, then Save. Converting several files? Save them all as one ZIP.

About the formats

WebM · WebM video

WebM is an open video format made for the web, using VP8/VP9 video and Opus or Vorbis audio.

M4A · MPEG-4 audio

M4A is an audio file in an MPEG-4 container, usually AAC. iTunes, Apple Music and Voice Memos use it.

The conversion runs on your device using FFmpeg compiled to WebAssembly. You can adjust: bitrate, sample rate, channels, normalise loudness, start at, end at.

Frequently asked questions

How do I convert WebM to M4A?

Drop your WebM files onto the page, or click “Choose files”. You can add many at once, or a whole folder. M4A is already selected as the output. Optionally open Options to adjust bitrate, sample rate, channels. Click Convert, then Save. Converting several files? Save them all as one ZIP.

Are my files uploaded to a server?

No. The conversion runs entirely in your browser using WebAssembly. Your files never leave your device, so it is safe for private photos, contracts and business data. Once the page has loaded it even works offline.

Will converting WebM to M4A reduce quality?

M4A uses lossy compression, so some detail is traded for a smaller file. At the default quality the difference is very hard to see or hear, and you can raise the quality setting if you need more.

Can I convert multiple WebM files to M4A at once?

Yes. Add as many WebM files as you like; they are converted in parallel on your device and you can download them all as a single ZIP.

Is it free? Are there limits?

It is free, with no sign-up, no watermark and no daily limits. Because nothing is uploaded there is no upload size limit either; the only limit is your device’s memory, which matters mostly for very large videos.

See everything the WebM converter and the M4A converter can do.