Your podcast host or directory rejects the episode because it is an Opus file, and Apple Podcasts, for example, only takes MP3 or AAC audio. The fix is to convert the .opus (or .ogg/.webm) recording to MP3, or to M4A if you prefer AAC, and upload that copy instead. You can do it in your browser, and the recording never leaves your device.
Why Opus gets rejected
Opus is a modern, efficient audio codec, used by WhatsApp voice notes and web calls. It sounds good at small sizes, but podcast directories and players are built around MP3 and AAC, so an Opus file is often refused at upload or flagged as an unsupported format. MP3 is the most compatible audio format there is, which makes it the safe choice for an episode.
Convert Opus to MP3 in your browser
Opus to MP3 ConverterConvert Opus audio, such as WhatsApp and Telegram voice notes (.opus, .ogg), to MP3 for any player or editor. Nothing is uploaded.Open tool- Open Opus to MP3 and drop your episode on the page, or click to browse. It accepts OPUS, OGG, WEBM and CAF files, and you can add several episodes at once.
- Adjust the quality if you like, then click Convert. Everything happens on your device.
- Download the MP3. If you want a different result, change the options and run it again on the same file.
The converter can also save as M4A, WAV or FLAC, so if your host asks for AAC, pick M4A (AAC audio in an MP4 container). For listening, MP3 at 128–192 kbps sounds good for most people.
The first time you use it, the converter engine (about 30 MB) is downloaded once and then cached. After that, speed depends on your device and the episode length.
If your recording came out as .ogg or .webm rather than .opus, the steps are the same: Opus to MP3 accepts both.
If the host wants M4A, WAV or another format
Audio ConverterConvert audio between MP3, M4A, WAV, FLAC, AIFF, CAF and OGG in your browser. Also reads Opus, AC-3, AU and WMA files.Open toolAudio Converter reads Opus and saves as MP3, M4A, WAV, FLAC, AIFF, CAF or OGG. Use it when your host lists a specific format, or when you want a WAV copy to edit before you export the final episode.
If the episode is too large to upload
Compress AudioMake MP3, WAV, M4A, FLAC and OGG files much smaller (64 kbps MP3) for email and messaging. Compressed on your device, never uploaded.Open toolCompress Audio makes audio files much smaller by saving them as 64 kbps MP3, and it accepts Opus too. Listen to the result before publishing, especially for episodes with music.
If you also want to strip old tags before publishing, Remove Metadata from Video & Audio removes title, artist, comments, chapters and cover art from MP3, M4A, OPUS and other audio files without re-encoding. You can then add your episode details in your podcast host.
About quality
Opus and MP3 are both lossy formats, so converting one to the other can't add back detail that was not recorded. Converting to FLAC or WAV doesn't help either: a lossy source keeps its original losses and just becomes a bigger file. If your recording app can export a lossless file or MP3 directly, that is the best source for future episodes. For existing Opus recordings, converting to MP3 at a sensible quality is the practical fix.
For more on the same conversion on a Mac, including voice notes, see How to Convert Opus to MP3 on a Mac. Other audio tools are in Video and audio tools.
Frequently asked questions
Are my podcast recordings uploaded anywhere?
No. The converter runs entirely in your browser using a WebAssembly build of FFmpeg, so your files never leave your device until you upload the finished MP3 to your podcast host yourself.
Can I convert a whole season at once?
Yes. You can add several files at once, and batch processing and ZIP downloads are included, so you can convert every episode in one go and download them together.
Does it work on a phone?
Yes. It works in any modern browser (Safari, Chrome, Edge, Firefox) on iPhone, iPad, Android, Mac, Windows and Chromebook, with nothing to install.