How to convert MP4 to M4A
- Drop your MP4 file.
- Adjust quality, resolution or bitrate if you want (defaults are optimized).
- Optionally set a start time and duration to trim.
- Click Convert, watch the progress and download your M4A file.
Why convert MP4 to M4A?
MP4 is excellent for sharing, uploading and playing video anywhere, but it has some limitations:
- Lossy compression
- Re-encoding reduces quality slightly
Converting to M4A gives you:
- Better quality than MP3 at the same size
- Native on Apple devices
MP4 vs M4A: side-by-side comparison
| Feature | MP4 | M4A |
|---|---|---|
| Full name | MPEG-4 Part 14 | MPEG-4 Audio |
| File extension | .mp4 | .m4a |
| Type | Video | Audio |
| Compression | Lossy (H.264/H.265) | Lossy (AAC) |
| Transparency | No | No |
| Animation / multi-frame | Yes | No |
| Introduced | 2001 | 2001 |
| Developed by | MPEG (ISO) | MPEG / Apple |
| MIME type | video/mp4 | audio/mp4 |
| Best for | sharing, uploading and playing video anywhere | Apple devices, voice memos and music |
What are MP4 and M4A files?
MP4 (.mp4)
MP4 is the most compatible video format today. Phones, YouTube, Facebook, WhatsApp and smart TVs all play MP4, usually with H.264 video and AAC audio.
M4A (.m4a)
M4A is an MPEG-4 audio file, usually containing AAC. iPhone voice memos, iTunes music and many recordings are M4A.
Tips for the best M4A results
- For phones and social media, MP4 (H.264 + AAC) is the safest choice for video and MP3 for audio.
- Very large files (over 1 GB) may exceed browser memory on phones; trim them or use a computer.
- 128 kbps is ideal for speech (lectures, waz, voice notes) and 192–320 kbps for music.
- Bookmark this page or install the app to convert MP4 files offline next time.
Private by design: how this converter works
Unlike typical online converters that upload your file to a remote server, this MP4 to M4A converter processes everything on your own device using FFmpeg compiled to WebAssembly — the same engine used by professional video tools. Your file is read into browser memory, converted, and offered back as a download — it is never sent to us.
- No upload wait — conversion starts instantly, even on slow mobile data.
- Private — safe for NID copies, certificates, bank statements and personal photos.
- No limits — no daily quota, no queue and no watermark.
- Offline-ready — once loaded, many tools keep working without internet.
Frequently asked questions
Is this MP4 to M4A converter free?
Yes — free, unlimited and without watermarks or sign-up.
Are my MP4 files uploaded to a server?
No. Conversion happens inside your browser on your own device, so your files stay private.
Will I lose quality converting MP4 to M4A?
M4A uses lossy compression, so a tiny amount of detail is discarded. At the default high quality setting the difference is practically invisible. Increase the quality slider for maximum fidelity.
Can I convert several files at once?
Yes. Drop multiple files and download them individually or together as a ZIP.
Does it work on iPhone and Android?
Yes. It works in Chrome, Safari, Edge and Firefox on phones, tablets and computers. You can also install the site as an app.
What is the difference between MP4 and M4A?
MP4 (MPEG-4 Part 14) is lossy (h.264/h.265) and best for sharing, uploading and playing video anywhere, while M4A (MPEG-4 Audio) is lossy (aac) and best for Apple devices, voice memos and music.
Why does the first conversion take longer?
The FFmpeg WebAssembly engine (about 30 MB) is downloaded once and cached. Later conversions start immediately.