M4A to OPUS converter
Turn M4A files into OPUS for free. The conversion runs entirely in your browser, so your audios are never uploaded anywhere.
How to convert M4A to OPUS
- Add your M4A files. Drop one or more .m4a files on the box above, or tap it to pick them from your device.
- Let it convert. The first audio you convert loads the converter once (about 31 MB, then cached). After that it runs on your device; a progress bar shows how far along it is.
- Download the OPUS. Press Download next to each file. Nothing was sent to a server, so close the tab and it's gone.
What is a M4A file?
M4A is AAC audio in an MP4 container. iPhones save voice memos and iTunes music as M4A.
What is OPUS?
Opus is the audio codec used by WhatsApp voice notes, Discord and video calls. It sounds great at very low bitrates.
Why convert M4A to OPUS?
M4A is great for Apple devices, with good quality at small sizes, but some Windows apps, older players and upload forms only take MP3. OPUS is the better choice for voice notes and calls; keep in mind many players, editors and upload forms don't accept .opus files.
Will I lose quality?
OPUS uses lossy compression tuned so the difference is invisible to the ear at normal use. We use high-quality settings by default.
Private by design
Most online converters upload your file to their servers. This one doesn't: the converter itself is loaded into your browser and works offline from there, so your audios never leave your phone or computer.
Questions
Is this M4A to OPUS converter free?
Yes, completely free, with no sign-up, no watermark and no daily limit.
Are my M4A files uploaded?
No. The conversion happens inside your browser on your own device. Nothing is sent to us or anyone else.
Can I convert M4A to OPUS on iPhone or Android?
Yes, in a modern browser. Phones are slower than computers for video, and very long videos can run out of memory on older phones.
Can I convert several files at once?
Yes. Drop as many as you like; they are converted one after another and each gets its own download button.
Is there a file size limit?
No fixed limit, but your browser has to hold the whole file in memory, so files over about 2 GB may fail.