Why do the bitrates look so low?

Because the codec is far more efficient than the older formats. It stays clean at rates where MP3 already sounds rough, so the useful range is 64 to 192 rather than 128 to 320. Higher rates would add size without adding much.

Why is variable bitrate the default?

Opus was designed around VBR. Letting the encoder decide where to spend bits is where its efficiency comes from, and the constant-rate mode exists mainly for links where the bandwidth cannot vary.

Where will an Opus file not play?

Older hardware, most car stereos and pre-smartphone portable players. Browsers, Android and desktop software are all fine, so the risk is only with unknown or aging devices.

Is Opus good for music as well as speech?

Yes. It was designed to handle both, which is unusual for a low-latency codec, and it is why libopus has become the default for so much real-time audio. Music at 128 kbps Opus is generally better than the same rate in MP3.

Does the file keep my tags and artwork?

Tags can be carried when metadata is set to preserve. Album art is not attempted for this container, so a picture embedded in the source will not appear in the output.

OPUS Converter

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OPUS Converter produces Opus audio, the codec behind most modern real-time voice and video, at bitrates where older formats are already struggling. It is the most efficient lossy option here.

What is OPUS Converter?

Drop a file, choose a bitrate, and encode. The output is an Opus file produced by libopus inside an Ogg container, which browsers, Android and desktop software all read.

The controls:

A bitrate ladder of 64, 96, 128 and 192 kbps, where 96 already sounds excellent.
A mode switch between variable and constant bitrate, with VBR as the default because that is how the codec was designed to run.
The shared advanced panel for channel mode, sample rate and metadata.

Opus is the most efficient codec on this site, and the ladder reflects that rather than ambition. It holds up at rates where MP3 falls apart, so 96 kbps Opus is comfortably better than 128 kbps MP3, and the scale tops out at 192 because higher numbers would mostly waste space. VBR is the natural mode: the encoder allocates bits according to demand, which is exactly where its efficiency comes from, and the constant-rate option exists mainly for fixed-bandwidth links that cannot tolerate variation. A constant rate is also useful when a file has to be split into fixed-size chunks for a delivery or storage system. Turning VBR off makes the size predictable at the cost of the efficiency that makes the format worth choosing. Sizes are correspondingly small, which is the headline benefit in practice. A 128 kbps file averages close to a megabyte per minute, and a 64 kbps voice recording can sit near half that, which is part of why the format made long-distance calls and shared voice notes practical in the first place.

The codec's other defining property is latency. Opus was standardised as RFC 6716 with both speech and music in mind and with real-time use as the target, which is why it ends up behind voice notes, group calls, screen sharing and modern video streaming rather than only in stored files. That design also means the encoder is comfortable at the low rates speech needs, and the container it is written into accepts the same rate ladders without complaint. For anyone delivering audio on the web the practical consequence is straightforward: the same perceptual quality arrives in a smaller download, so a listener on a poor connection hears less stalling and fewer artefacts than an older codec would give them at the same bandwidth. That is the whole argument for moving a streaming library over, once the players in use can read it.

The compatibility picture is the mirror of its strengths. Modern browsers, Android and desktop software all handle Opus well, while older hardware, most car stereos and older portable players do not. For anything that has to work on unknown or aging devices, MP3 remains the safer target. As the format has no in-process encoder here, the conversion runs through the bundled ffmpeg core, which downloads once and is cached by the browser afterwards.

Where it stops:

Poor support on older hardware, car stereos and pre-smartphone devices.
Lossy output, so it is not an archiving format.
The bitrate ladder stops at 192 kbps, deliberately.
One file per run.
No album art passthrough, so cover art is not carried into the output.

How to use OPUS Converter

Drop an audio file onto the panel.
Choose a bitrate, keeping 96 kbps for most material since the codec is efficient.
Leave variable bitrate on unless a fixed-bandwidth link requires otherwise.
Convert and play the result back before deleting the source.

When to use OPUS Converter vs related tools

OPUS Converter is the best lossy choice when the playback target is modern and size matters most, which covers web audio, voice material and mobile apps. OGG Converter is the older open alternative with slightly wider legacy support, MP3 Converter is the format to fall back on when the destination is unknown, and Streaming Bitrate Calculator works out what a given rate costs per listener before you publish.

Privacy & Security

This tool runs entirely in your browser — no data ever leaves your device. There is no server round-trip, no upload, no logging, and no account required. Your input is processed locally using client-side JavaScript and is never stored, transmitted, or accessible to anyone else. When you close the tab, everything disappears.