Convert Opus to MP3 Free Online

This audio conversion utility transforms Opus-encoded audio files into the universally compatible MP3 format using FFmpeg WebAssembly technology for client-side processing. Opus is a modern, highly efficient lossy codec commonly found in WhatsApp voice messages, Telegram audio, Discord recordings, and WebRTC communication streams. Despite its superior compression efficiency, Opus lacks native playback support on many older devices, car stereos, and legacy media software.

The tool provides four selectable MP3 bitrate options ranging from 128kbps for compact files to 320kbps for maximum audio fidelity. Internally, the FFmpeg engine decodes the Opus stream and re-encodes it using the LAME MP3 encoder at 44.1kHz stereo, matching CD-quality sample rate specifications. A real-time progress indicator tracks the encoding pipeline from engine initialization through final file assembly.

The converted MP3 file is presented with an embedded HTML5 audio player for immediate preview before download. File size statistics for both the original Opus and the resulting MP3 are displayed side-by-side. The entire conversion chain—from file ingestion through LAME encoding to Blob creation—executes locally within the browser sandbox, ensuring complete privacy for voice messages and personal audio recordings.