OPUS to M4A Converter
Convert OPUS to M4A locally in your browser, powered by Mediabunny and native WebCodecs — nothing is ever uploaded. Drop a OPUS file below to get started.
Drop files, or click to browse
OPUS files only — processed one at a time
Frequently asked questions
Is this OPUS to M4A converter free?+
Yes, with no watermark, no account, and no daily limit.
Is my audio file uploaded anywhere?+
No — conversion runs locally using your browser's own built-in media codecs, entirely inside your browser tab.
Will I lose audio quality?+
Converting between compressed formats can lose a small amount of quality; converting to a lossless format like WAV or FLAC won't.
Is there a maximum file size?+
There's no fixed file-size limit since nothing is uploaded to a server. Processing time scales with the track's length rather than a hard cutoff.
How do I convert OPUS to M4A?+
Drop your OPUS file into the box above — it's decoded and re-encoded as M4A automatically, with a download ready in seconds.
About OPUS and M4A
What is OPUS?
Opus is a modern, royalty-free codec built for both music and speech, widely used in video calls and voice messaging.
Full OPUS format guide →What is M4A?
M4A is an audio-only MPEG-4 container, most often holding AAC audio — it's what Apple Music and Voice Memos save by default.
Full M4A format guide →The short version: M4A gives you good compression efficiency, which helps once you run into OPUS's biggest limitation: less common as a general music-library format. It's a natural move when your audio is headed toward voice memos and Apple Music downloads.
How it works
- 1
Drop your file in
Drag your audio onto the box above, or click it to browse — there's no account to create and no upload to wait on.
- 2
Pick your settings
The output format is already set for this page — just adjust any extra options shown, if there are any.
- 3
Download the result
Your browser processes everything locally and hands you a download link the moment it's done — nothing was ever sent to a server.
Is it private?
Everything happens locally, inside this browser tab. Your audio is read from disk, processed with WebAssembly running on your own device, and handed back to you as a download — it's never transmitted anywhere, so there's nothing to intercept and nothing stored on a server.
Common use cases
- Voice memos and Apple Music downloads
- Podcasts
- Prepping a podcast episode for a hosting platform
- Fitting a voice memo under a messaging app's size limit
Supported formats
This is one of many pairings the audio toolkit handles. In total it covers:
Related conversions
Format details
About OPUS files+
Opus is a modern, royalty-free codec built for both music and speech, widely used in video calls and voice messaging.
Opus was developed by the IETF and the Xiph.Org Foundation to unify what used to be two separate problems — speech codecs and music codecs — into a single format that performs well at both, with very low latency. That low latency and strong quality at low bitrates is exactly why it's become the default codec behind most modern video and voice calling: WhatsApp, Discord, Google Meet, and many others all rely on it under the hood, even when users never see the format name at all.
How to open a OPUS file
Opens readily in VLC Media Player, Most modern browsers and media players. For real editing, use Audacity (with recent versions).
Good for
- excellent quality at low bitrates
- low latency, ideal for real-time audio
Watch out for
- less common as a general music-library format
About M4A files+
M4A is an audio-only MPEG-4 container, most often holding AAC audio — it's what Apple Music and Voice Memos save by default.
M4A is essentially an MPEG-4 container that's been restricted to audio only, and it's the extension Apple uses by default across iTunes downloads, Apple Music, GarageBand, and Voice Memos. In almost every practical case it holds AAC-encoded audio, so its quality and compression characteristics are effectively the same as AAC — it's really a matter of which extension a given piece of Apple software happened to save the file with.
How to open a M4A file
Opens readily in Any modern media player, iTunes/Apple Music, Most web browsers. For real editing, use Audacity (free), GarageBand.
Good for
- good compression efficiency
- native format across Apple apps
Watch out for
- occasionally needs converting for apps that only expect MP3
Need a different format? Try the full Audio Converter, or explore all audio tools.