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Supports: AAC, AC3, AIF, AIFC, AIFF, AMR +13 more
A catch-all audio-to-Opus converter: bring almost any sound file — MP3, WAV, FLAC, AAC, M4A, M4B, OGG, OPUS, AIFF, AC3, AMR, AU, VOC, WEBA, or WMA — and get back an .opus file. Unlike a legacy target, Opus is the modern, recommended audio codec (IETF RFC 6716, standardized September 2012), and it beats MP3 on quality-per-byte at every bitrate. The short answer: if everything that will play the file is reasonably current — a recent browser, an Android 10+ phone, a Discord or web-streaming pipeline — convert to Opus and ship a smaller file at the same quality. If an older car stereo, a basic MP3 player, or a pre-2024 iPhone has to play it, stay on audio to MP3 instead. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared or made public.
| Property | Opus | MP3 |
|---|---|---|
| Standardized | IETF RFC 6716, September 2012 | ISO/IEC MPEG-1/2 Layer III, early 1990s |
| Underlying tech | SILK (speech) + CELT (music), auto-switched | MDCT-based perceptual coding |
| Bitrate range | 6–510 kbps (CBR or VBR) | 8–320 kbps |
| Licensing | Royalty-free, open source | Patents expired (2017), now freely usable |
| Quality at low bitrate | Excellent — ~64 kbps rivals MP3 ~128 kbps for music | Audible artifacts below ~128 kbps |
| Sample rates / channels | 8–48 kHz, up to 255 channels | 8–48 kHz, mono/stereo |
| Browser support | Chrome 33+, Firefox 15+, Edge 14+; Safari partial, iOS Safari full from 18.4+ | Universal — every browser and device |
| Best for | Streaming, podcasts, voice chat, web audio, storage savings | Maximum compatibility, legacy hardware, car stereos |
.opus — some still only accept MP3 or AAC.Better, by a measurable margin on efficiency. Opus combines two engines — SILK for speech and CELT for music — and switches between them automatically, which lets it hold quality at bitrates where MP3 starts to sound rough. In standardized listening tests, Opus near 64 kbps is competitive with MP3 around 128 kbps for music, and by ~128 kbps Opus is effectively transparent. MP3's one lasting advantage is reach: it plays on practically every device ever made, while Opus needs reasonably modern playback support.
Some, unavoidably, because this is a lossy-to-lossy re-encode. Your MP3 or AAC source has already discarded data through its own compression, and Opus cannot rebuild detail that's already gone — it can only preserve what's left. To minimize a second round of loss, encode to Opus at a bitrate that matches or exceeds the source. The only genuinely clean, first-generation Opus encode comes from a lossless source such as WAV, FLAC, or AIFF, where the encoder works from a pristine master.
In recent browsers and on modern mobile: Chrome 33+, Firefox 15+, and Edge 14+ play Opus in the HTML audio element, and Android has supported it since version 10. Apple was the holdout — desktop Safari shows only partial support, and iOS Safari gained full Opus playback in the audio element starting with version 18.4 (early 2025). Older car stereos, basic MP3 players, and pre-2024 iPhones often can't play it at all. If wide compatibility matters more than file size, convert audio to MP3 instead.
It depends on the content. For spoken-word audio — podcasts, audiobooks, voice notes — Opus stays clean at surprisingly low bitrates, and 24–48 kbps is often plenty. For music, aim for VBR in the 96–128 kbps range, which is typically transparent; pushing past ~160 kbps yields diminishing returns because Opus is already efficient. Opus supports anything from 6 kbps up to 510 kbps, so you have room either way. If you'd rather target a file size than a bitrate, use the Specific file size option under File Compression.
The codec is identical — what changes is the container. A .opus file is Opus audio wrapped in the lightweight Ogg container, which is the standard way to ship a standalone Opus track. Opus can also live inside .ogg, .webm, or .caf files, which is how it's commonly delivered for web video and streaming. This tool outputs the standalone .opus form; if you specifically need Opus audio in an OGG or WebM container for a web project, convert to those targets instead.
Yes. If every file you're converting is the same type, the dedicated pages skip straight to that pair: MP3 to Opus for the most common case, WAV to Opus for a clean lossless-to-Opus encode, or FLAC to Opus for compressed lossless masters. This generic page handles the catch-all case — mixed formats, or a file whose type you're unsure of. In our testing, a 4-minute track encoded to Opus VBR at 128 kbps lands around 3.8 MB while staying perceptually close to a 320 kbps MP3 of the same audio — roughly a third of the MP3's size at comparable quality.
Your file is uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared or made public.