Converts Opus files to MP3 format — voice-over-IP, real-time communication, and streaming at very low bitrates with excellent quality to universal music playback and sharing across all devices and platforms. All conversion happens locally in your browser with no file size limits.
Runs on FFmpeg
Content reviewed October 2026 · About Toolzum
Convert MP3 audio files to OPUS format directly in your browser. Audio never leaves your device — conversion and editing run locally in your browser with FFmpeg WASM. Private and free. for voice streaming and bots.
Convert M4A audio files to OPUS format directly in your browser. Audio never leaves your device — conversion and editing run locally in your browser with FFmpeg WASM. Private and free. for efficient voice streaming.
Convert WMA audio files to MP3 format directly in your browser. Audio never leaves your device — conversion and editing run locally in your browser with FFmpeg WASM. Private and free.
Convert MP4/WebM to GIF animations. Videos up to 250MB. Videos never leave your device — compression and conversion run locally in your browser with FFmpeg WASM.
Extracts the audio track from MP4 video files and saves it as a standalone MP3 file. All processing runs locally in your browser with FFmpeg WASM — nothing is uploaded.
Opus (Opus Interactive Audio Codec) uses lossy compressed encoding and is best for voice-over-IP, real-time communication, and streaming at very low bitrates with excellent quality. MP3 (MPEG-1 Audio Layer 3) uses lossy compressed encoding and excels at universal music playback and sharing across all devices and platforms. Converting between them lets you take advantage of each format's strengths — for example, using a compressed format for sharing and a lossless format for editing. All conversion happens locally in your browser with no file size limits.
Opus shines in VoIP and streaming — MP3 plays everywhere else.
Low-bitrate voice sources stay intelligible; music sources deserve high bitrates.
Opus voice recordings convert cleanly; music was already compromised at low rates.
No — conversion runs locally in your browser; unlimited saves on local tools.
Text to Speech (TTS)
Generate natural-sounding speech from text using your browser's built-in voices. Adjust speed and pitch — download your text as .txt.
Audio Cutter
Trim and cut audio files online — MP3, WAV, M4A, FLAC, and OGG. Set start and end times with sliders, then download the trimmed MP3 clip.
MP3 to WAV
Converts MP3 files to WAV format — universal music playback and sharing across all devices and platforms to professional audio editing, mastering, and archival in DAWs and production software. All conversion happens locally in your browser; files up to 100 MB each.
Speech to Text
Dictate live microphone speech to text in multiple languages through your browser's speech service. Live captions for meetings and notes — free to start, no Toolzum account needed.
MP3 Compressor
Shrink MP3 files by lowering bitrate with quality presets — fit podcasts into feed limits. Cut a 50 MB episode to 15 MB cleanly — local FFmpeg work, unlimited saves.
Apple Music Preview Extractor
Extracts publicly available 30-second audio preview clips from Apple Music by resolving the store URL. Free to start with no signup.