Free online MP3 to OPUS converter

A voice, messaging, browser-based, or streaming application may require an .opus file instead of an MP3. Conversion can also reduce the size of speech and music files for online distribution, but it cannot restore audio detail already discarded by MP3 encoding.

What the MP3 format is

MP3 (MPEG-1 Audio Layer III) is a lossy audio format usually stored with the .mp3 extension. Phones, music players, podcast software, media libraries, CD-ripping tools, and older audio editors commonly support it. Its broad hardware and software compatibility makes it a frequent source format, although its compression has already removed some audio information.

What the OPUS format is

Opus is a royalty-free, lossy audio codec designed for both speech and music. An Opus stream is commonly stored in an Ogg container with the .opus extension. It supports low-delay voice communication, conferencing, gaming chat, and streaming, while also delivering high-quality stereo audio at moderate bitrates. At comparable perceived quality, Opus often creates smaller files than MP3, but older players, hardware, and editing applications may not support it.

How to convert MP3 to OPUS

You can convert the file on 101convert.com for free without installing software. Open the converter, select the MP3 file, choose OPUS as the output format, start the conversion, and download the resulting .opus file when processing is complete. Avoid uploading confidential recordings unless the service's file-handling terms meet your requirements.

For local conversion and batch processing, FFmpeg provides direct control over the Opus encoder and bitrate. Run:

ffmpeg -i input.mp3 -map 0:a:0 -c:a libopus -b:a 96k output.opus

Replace the input and output filenames as needed. The -map 0:a:0 option selects the first audio stream and avoids treating embedded album art or other streams as audio. Typical starting points are 48k to 64k for speech, 96k for general stereo audio, and 128k to 160k for higher-quality music. The command decodes the MP3 and then encodes the decoded audio with Opus.

On a Unix-like shell, this command converts every lowercase .mp3 file in the current directory:

for f in *.mp3; do ffmpeg -i "$f" -map 0:a:0 -c:a libopus -b:a 96k "${f%.mp3}.opus"; done

Audacity is an alternative graphical tool. Open the file with File → Open, then choose File → Export Audio, select Ogg Opus as the file type, set the bitrate, and save. The exact export label depends on the Audacity version; if an Opus export option is unavailable, use FFmpeg instead.

Quality and compatibility considerations

MP3-to-Opus is a lossy-to-lossy conversion. The Opus encoder receives audio that has already been altered by MP3 compression, so it cannot reproduce the quality of the original recording. If a WAV, FLAC, or other lossless source exists, encode that source directly to Opus.

Increasing the Opus bitrate generally preserves more detail and produces a larger file, but it cannot remove MP3 artifacts such as pre-echo or smeared high frequencies. Choose the bitrate according to the content and test the result in the target application, because support for Ogg Opus and the .opus extension varies among older players, embedded devices, and editing programs.