To convert an OPUS file to MP3 on iPhone, share it to Grabio, pick Audio → MP3 (open VERT), then upload the file on VERT and choose MP3. The MP3 step runs on VERT in Safari, because Apple’s Shortcuts has no MP3 encoder. Opus is a good format, so first check that you really need MP3.

At a glance

Cost
Free, forever
Account
None needed
App Store
No install
MP3 step runs on
VERT (vert.sh) in Safari

An.opus file is audio in the Opus codec. You tend to meet one when someone sends you a recording or a download and your player or editor does not list the format. Converting a copy to MP3 is the usual fix.

Convert OPUS to MP3 on iPhone, Free

1. Share the.opus file to Grabio2. Audio → MP3(open VERT)3. Upload, pick MP3,download

Do I need to convert OPUS to MP3?

At a glance

Cost
Free, forever
Account
None needed
App Store
No install
Runs on
iPhone, via Shortcuts
OPUSGrabioMP3
OPUS in, MP3 out, on your iPhone

Only if the place you want to use the file will not take it. Opus is a lossy codec standardised by the IETF as RFC 6716, and MDN lists it as usable inside WebM, MP4 and Ogg containers. It is not a poor format. The problem is usually a player, an editor or an upload form that lists MP3 and nothing else.

If you are not sure, try the file where you need it first. If it fails, convert a copy and keep the original. If the problem is a different kind of audio, see convert audio to MP3 on iPhone, or convert M4A to MP3 for Voice Memos.

How do I convert OPUS to MP3 on iPhone?

  1. Add Grabio once. It is a free Apple Shortcut with no sign-up: grabio.adityaarsharma.com/get-shortcut.
  2. Find the.opus file in Files and tap Share.
  3. Tap Grabio. If it asks which type of file this is, choose Audio / Music.
  4. Pick Audio → MP3 (open VERT) from the menu.
  5. Read the short prompt, then let Safari open VERT.
  6. On VERT, tap Upload, pick your.opus file, choose MP3 as the output and convert.
  7. Download the MP3. Safari normally saves it to the Downloads folder in the Files app.

Step 6 is manual on purpose. iOS does not let a shortcut drop a file into a website’s upload box, so you pick it yourself. It is one extra tap, not a fault.

Opus vs MP3: what is the difference?

Both are lossy, so neither keeps every detail of the original sound. The table uses what MDN says about each codec.

Question Opus MP3
What it is Codec made by Xiph.Org, standardised as IETF RFC 6716 MPEG-1 Audio Layer III
Lossy or lossless Lossy Lossy
Bit rates MDN lists 6 to 510 kbps 32 to 320 kbps (MPEG-1 mode), 8 to 160 kbps (MPEG-2 mode)
Variable bit rate Yes Yes
MDN’s minimum for stereo 96 kbps at 48 kHz 128 kbps at 48 kHz
Converted on the iPhone itself Not with Grabio No, via VERT

Source: MDN, Web audio codec guide, read 7 Nov 2026. Because both are lossy, converting an Opus file to MP3 encodes the sound a second time, so do it once from the original.

Will the MP3 sound worse than the OPUS?

In theory a little, since the audio is lossy-encoded again. For speech such as a voice note or a lecture it is hard to notice. For music you care about, convert only when something forces you to, and keep the.opus original.

Is it private to convert OPUS to MP3 with Grabio?

Grabio never receives your file. The server only hands out the shortcut and counts anonymous hits. The file goes to VERT in your browser. VERT’s own README says it converts files on your device using WebAssembly instead of a cloud, and also says some conversions may need server-side processing on its official instance. Check VERT yourself if the recording is sensitive.

Convert OPUS to MP3 on iPhone: FAQ

Can I convert OPUS to MP3 on iPhone without an app?

Yes. Grabio is a Shortcut, not an App Store app, and VERT runs in Safari. Nothing to install from the App Store, and no account for either.

Does VERT support OPUS and MP3?

Yes. VERT’s published source lists both opus and mp3 as formats it handles, as read on 7 Nov 2026.

Why does Grabio open a website for MP3?

Shortcuts cannot encode MP3. Grabio hands that one format to VERT instead of faking it.

Where does the MP3 end up on my iPhone?

VERT downloads it through Safari, so it normally appears in the Downloads folder in the Files app. From there you can move it or share it.

Should I delete the OPUS file afterwards?

No. Keep it as your original, and use the MP3 as a copy for the place that needs it.

Related on iPhone: convert audio to MP3, MP3 vs M4A, convert M4A to MP3, convert audio to M4A, convert MP4 to MP3, convert any file format, or Video & Audio Tools.