OPUS Compressor
Compress audio to OPUS format online for free — the most efficient lossy audio codec, typically 30% smaller than MP3 at the same quality. Choose from 8 bitrate presets from 6 to 128 kbps, each showing the equivalent MP3 bitrate. Runs entirely in your browser with no signup required.
Drop your audio file here
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MP3, WAV, M4A, OGG, FLAC, WebM — any audio format
Why Use Our OPUS Compressor?
Instant OPUS Compression
Compress audio to OPUS format instantly in your browser — no upload wait, no server queue. The opus compressor processes your audio using the Web Audio API and MediaRecorder, delivering the compressed file in seconds.
Secure OPUS Compressor Online
Your audio never leaves your device. The opus compressor runs entirely in your browser — no server uploads, no data transmission, 100% private. Safe for confidential recordings, music, and proprietary audio content.
30% Smaller Than MP3 at Same Quality
OPUS achieves the same perceived audio quality as MP3 at approximately 30% lower bitrate. The opus compressor shows the equivalent MP3 bitrate for each OPUS preset so you can understand the quality-size tradeoff.
100% Free Forever
The opus compressor is completely free with no signup, no premium tier, no file size limits, and no ads. Compress unlimited audio files to OPUS format at zero cost, forever.
Common Use Cases for OPUS Compressor
Web Audio Delivery
Compress audio assets for web delivery using OPUS — the format natively supported by all modern browsers. The opus compressor produces smaller files than MP3 at the same quality, reducing bandwidth costs and improving page load times.
Mobile App Audio
Compress audio for mobile apps where bandwidth and storage are limited. OPUS at 48–64 kbps delivers music quality comparable to MP3 at 96–128 kbps — the opus compressor helps you hit mobile data budget targets.
Podcast and Streaming
Compress podcast episodes and streaming audio to OPUS for maximum efficiency. The opus compressor at 32–48 kbps delivers clear speech quality comparable to MP3 at 64–96 kbps, reducing hosting and CDN costs.
Cloud Storage Optimisation
Reduce audio storage costs by converting to OPUS before uploading to cloud storage. The opus compressor produces the smallest possible audio files while maintaining perceptual quality for music and speech.
Voice and Communication
OPUS was originally designed for real-time voice communication and excels at low bitrates. The opus compressor at 6–24 kbps produces intelligible voice recordings smaller than any other lossy codec.
Game and App Audio
Compress game sound effects and app audio to OPUS for smaller download sizes. The opus compressor produces WebM/OPUS files that play natively in all modern browsers without additional plugins.
Understanding OPUS Audio Compression
What is OPUS?
OPUS is an open, royalty-free audio codec standardised as RFC 6716 by the IETF. It was developed by Xiph.Org and Mozilla and is the most efficient lossy audio codec available — achieving the same perceived quality as MP3 at approximately 30% lower bitrate. OPUS combines the SILK codec (optimised for speech) and the CELT codec (optimised for music) into a single adaptive codec that automatically selects the best algorithm for the content. It is natively supported by all modern browsers, WebRTC, Discord, Zoom, and most streaming platforms. The opus compressor uses the browser's native MediaRecorder API to encode audio to OPUS without any server-side processing.
How Our OPUS Compressor Works
- Upload Your Audio: Drop any audio file — MP3, WAV, M4A, OGG, FLAC, or WebM — into the upload zone. The opus compressor accepts any format that your browser can decode via the Web Audio API.
- Select Target Bitrate: Choose from 8 bitrate presets (6–128 kbps). Each preset shows the equivalent MP3 bitrate so you can understand the quality-size tradeoff. OPUS at 64 kbps is roughly equivalent to MP3 at 90 kbps.
- Download Compressed Audio:Click "Compress to OPUS" and the tool resamples your audio to 48 kHz (OPUS's native sample rate), encodes it using the browser's MediaRecorder API, and downloads the compressed file automatically. Your audio never leaves your device.
OPUS vs MP3 vs OGG — Which to Choose?
- OPUS: Best overall efficiency — 30% smaller than MP3 at the same quality. Ideal for web delivery, streaming, and any use case where file size matters. Supported by all modern browsers natively.
- MP3: Universal compatibility — works on every device including older hardware, car stereos, and legacy systems. Use MP3 when maximum compatibility is required.
- OGG Vorbis: Good quality at medium bitrates — comparable to MP3 but with slightly better quality at 128+ kbps. Less efficient than OPUS at low bitrates.
- AAC:Apple's format — used in M4A files and Apple Music. Slightly better than MP3 at the same bitrate but less efficient than OPUS.
Browser Compatibility
The opus compressor uses the browser's native MediaRecorder API to encode OPUS. This is supported in Chrome, Edge, and Firefox. Safari has limited MediaRecorder support and may not support OPUS encoding. If your browser does not support OPUS encoding, the tool will display an error message — in that case, use Chrome or Firefox for best results.
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Frequently Asked Questions About OPUS Compressor
An opus compressor converts audio files to OPUS format — the most efficient lossy audio codec, typically 30% smaller than MP3 at the same quality. Our free opus compressor online uses the browser's native MediaRecorder API to encode audio to OPUS entirely in your browser — no server upload, no installation required.
OPUS achieves the same perceived audio quality as MP3 at approximately 30% lower bitrate. For example, OPUS at 64 kbps sounds roughly equivalent to MP3 at 90 kbps. At very low bitrates (6–24 kbps), OPUS is dramatically better than MP3 — it was specifically designed for voice communication at low bitrates.
Absolutely. The opus compressor processes everything locally in your browser — your audio is never uploaded to any server and never leaves your device. Completely safe for confidential recordings, music, and proprietary audio content.
Yes — 100% free, forever. No signup, no account, no premium tier, no file size limits, and no ads. Compress unlimited audio files to OPUS format completely free.
For music, 64–96 kbps OPUS provides high quality comparable to MP3 at 96–128 kbps. For near-transparent quality, use 96–128 kbps. For voice-only content like podcasts and audiobooks, 32–48 kbps is sufficient and produces very small files.
Chrome, Edge, and Firefox support OPUS encoding via the MediaRecorder API. Safari has limited MediaRecorder support and may not support OPUS encoding. If you see an error about browser support, switch to Chrome or Firefox for best results.
The output format depends on your browser. Chrome and Edge typically produce WebM containers (.webm) with OPUS audio. Firefox may produce OGG containers (.opus). Both formats contain OPUS audio and are playable in all modern browsers. The opus compressor names the file with the correct extension automatically.
OPUS files play natively in all modern browsers (Chrome, Firefox, Edge, Safari 14+) and most modern media players. Older devices and some car stereos may not support OPUS. For maximum compatibility, use MP3 instead. For web delivery and modern apps, OPUS is the recommended format.
There is no artificial file size limit. The practical limit depends on your browser's available memory. For typical use cases — songs, podcasts, voice recordings — the opus compressor handles them instantly. Very long recordings (several hours) may take a moment to process.