M4A to OPUS Converter
Convert MPEG-4 Audio (M4A) to Opus Interactive Audio Codec (OPUS) online for free. Runs 100% in your browser. Files never leave your device. No signup, no watermarks, no limits.
Drag & drop files here, or browse
Processed on your device. Nothing is uploaded
Automate this. An open tab can convert whole folders via the Local API - still zero uploads.
Local API →How to use M4A to OPUS Converter
- 01Add files
Choose files or drop them here
- 02Settings
Settings · Runs on your device
- 03Download
Processed on your device. Nothing is uploaded
What is a M4A (MPEG-4 Audio) file?
M4A is an MP4 container holding AAC (or lossless ALAC) audio. The standard for iTunes and iPhone voice memos.
- Developed by
- Apple
- Initial release
- 2001
What is a OPUS (Opus Interactive Audio Codec) file?
Opus is a modern, open codec optimized for both speech and music at very low bitrates. It powers Discord, WhatsApp voice messages and much of WebRTC.
- Developed by
- IETF / Xiph.Org
- Initial release
- 2012
Frequently asked questions
How do I convert M4A to OPUS?
Click “Choose Files” or drag your M4A file onto the page, optionally adjust the settings, then hit Convert. Your OPUS file downloads straight from your browser. Nothing is uploaded anywhere.
Is this M4A to OPUS converter free?
Yes, completely free with no hidden limits, watermarks or signup. Because all processing happens on your own device, there are no server costs to pass on to you.
Are my files uploaded to a server?
No. The conversion engine runs entirely in your web browser using WebAssembly. Your files never leave your device. You can even disconnect from the internet after the page loads and keep converting.
Is there a file size limit?
We impose no fixed limit. The practical ceiling is your device's free memory, since processing happens locally. Most conversions work comfortably with files up to a few hundred megabytes, and image or document conversions handle much more.
Does it work on my phone?
Yes. The converter runs in any modern browser on Windows, macOS, Linux, Android and iOS. No app installation is required.