Two very different kinds of OGG file
An .ogg file is a container, and what's inside it decides how it should be
converted. Most hold one of two things:
| Inside the OGG | Where it comes from | Typical bitrate | MP3 it gets here |
|---|---|---|---|
| Vorbis | Game soundtracks and sound effects, Linux apps, Wikimedia Commons recordings, older music downloads | 96–192 kbps stereo | Matched: about a quarter higher, rounded up (112 kbps → 160 kbps) |
| Opus | WhatsApp and Telegram voice notes (.opus or .ogg), some recorders | 16–32 kbps mono | 64 kbps mono, clear for speech |
Many converters treat both the same and encode everything at one fixed bitrate. That wastes space on voice notes and can shortchange music. Here each file is opened first, and the result tells you what it found: the codec, channels, sample rate and bitrate of the original.
WhatsApp and Telegram voice notes
Voice messages are Opus audio, recorded in mono. On Android, WhatsApp keeps them in the
WhatsApp Voice Notes folder as .opus files (named like
PTT-20261009-WA0003.opus); WhatsApp and Telegram on a computer usually save
them as .ogg. Either works here. The MP3 stays mono and is encoded at
64 kbps, about half a megabyte per minute, so a long message still fits in an email.
One thing that surprises people: the MP3 is bigger than the voice note. Opus was built for speech and gets a voice into very few bits. In our test a 20-second voice note recorded at about 19 kbps was 46 KB; the MP3 was 160 KB, three and a half times larger. That's expected; much below 64 kbps, MP3 speech starts to sound muffled. Convert voice notes when something needs MP3 (an editing app, a transcription service, a court or HR upload form), not to save space.
Music and game audio in Ogg Vorbis
For Vorbis files, Match the original reads the bitrate and adds about a quarter, because MP3 is a little less efficient, then rounds up to the next standard setting. Our 112 kbps test file became a 160 kbps MP3. Picking 320 kbps for a 112 kbps original only makes the file twice as large; the sound can't get better than the original, and the result says so when you do it.
Opus always runs at 48 kHz and Vorbis usually at 44.1 or 48 kHz, and MP3 supports both, so nothing is resampled. Every MP3 is decoded again after encoding and checked for peaks that go past full scale; if it would clip, the volume is lowered just enough. Most voice notes and game files never need it, but loud music sometimes does.
Tags and cover art
OGG files keep their tags as Vorbis comments, and the cover image in a field called
METADATA_BLOCK_PICTURE, which many converters skip. Here the title, artist,
album, album artist, track and disc number, genre, year, comment and cover art are written
into the MP3's ID3 tag. We checked a tagged file with an independent tag reader: every
field arrived, and the cover was copied byte for byte. Voice notes have no tags, and the
result says so instead of inventing any.
Many files at once
Drop a folder of voice notes or a whole soundtrack and they're converted one after another, each with its own result line and player so you can check it. Download all as ZIP saves them together, named after the album when the files share one. The MP3s start exactly where the originals do: the encoder's short lead-in is marked so players skip it.
Private messages stay private
Voice notes are often personal. Nothing is uploaded here: the files are decoded and encoded in your browser, with a WebAssembly build of the LAME MP3 encoder. There's no account or file limit. For other formats, see M4A to MP3, FLAC to MP3 and WAV to MP3; to cut a recording first, use Trim audio.