Audio conversion uses FFmpeg through the single-threaded @ffmpeg/core 0.12.10 build, licensed under GPL-2.0-or-later. FFmpeg. ffmpeg.wasm.
Voice notes exported from WhatsApp often arrive as .opus files, and so do recordings from some call and VoIP apps. Many players, editors, transcription tools and email recipients cannot open them. This free OPUS to MP3 converter makes an MP3 copy that plays anywhere. Voice notes are personal, so this page never uploads them: the conversion runs in your browser. For .ogg files, use OGG to MP3.
How do I convert an OPUS voice note to MP3?
- Save the voice note to your phone or computer first (for example, Share > Save to Files on iPhone, or your file manager on Android).
- Open this page, click Browse files and choose the .opus file.
- Choose 128 kbps under Audio quality. It is plenty for speech.
- Click Convert to MP3, then Download MP3.
What is an OPUS file?
Opus is an open, royalty-free audio codec standardized by the IETF in 2012 as RFC 6716. It was built for the internet: it handles everything from low-bitrate speech to full-band music and keeps delay very low, which is why calling and messaging apps use it. A .opus file is normally Opus audio in an Ogg container, as described in RFC 7845.
How do I open a .opus file?
Recent versions of Chrome, Firefox and Edge can play it, and VLC opens it on any computer. Many other apps cannot, including some built-in phone players and older Windows Media Player versions. Converting to MP3 is the simple, universal fix.
Why is the MP3 bigger than my voice note?
Opus is much more efficient than MP3. Voice notes are usually recorded at low bitrates, so the .opus file is tiny. In our test, a one-minute mono Opus file at 32 kbps weighed 223,459 bytes. Its MP3 at 128 kbps weighed 960,931 bytes, more than four times as much. That is still under 1 MB per minute, small enough for any email or chat.
| Voice note length | MP3 at 128 kbps |
|---|---|
| 30 seconds | about 0.5 MB |
| 2 minutes | about 1.9 MB |
| 10 minutes | about 9.6 MB |
Is OPUS better than MP3?
On quality per megabyte, yes, by a wide margin, especially for voice. MP3 wins on compatibility. Keep the original if your apps play it, and convert when you need to share it with someone or something that only takes MP3.
Will the MP3 sound worse than the voice note?
Not noticeably at 128 kbps. Voice notes are recorded at low quality to start with, and MP3 at 128 kbps keeps speech clear. Choosing 320 kbps would only make the file bigger.
Limits of the OPUS to MP3 page
This page accepts .opus files only, up to 150 MB and one at a time. It does not download voice notes from WhatsApp or any app: save the file first, then convert it. For other formats, use the main MP3 converter.
Frequently asked questions about OPUS to MP3
Is this OPUS to MP3 converter free?
Yes. It is free with no sign-up, and the conversion runs in your browser.
Are my voice notes uploaded?
No. The .opus file stays on your device and the MP3 is created in your browser.
Can I convert a WhatsApp voice note to MP3?
Yes. Save the voice note as a file, open this page, choose the .opus file and convert it.
What bitrate should I use for voice notes?
128 kbps. It keeps speech clear with the smallest file.
Is OPUS better or MP3?
Opus sounds better at the same bitrate. MP3 plays on more devices and apps.
Can I convert OPUS to MP3 on my iPhone?
Yes. Save the voice note to Files, open this page in Safari, choose the file and convert it. The MP3 is saved in Files > Downloads.
Convert your OPUS file to MP3
Choose the voice note, pick a bitrate and download an MP3 anyone can play.
Other audio to MP3 converters
- OGG to MP3: Vorbis and Opus audio in .ogg files.
- M4A to MP3: iPhone voice memos.
- WEBM to MP3: browser recordings with Opus audio.
- Audio to MP3 converter: every audio format in one place.