Upload a OGG file and get a M4A back. No signup, no watermark, no limit on how many.
OGG here means Vorbis audio in an Ogg container — a patent-free lossy codec that generally beats MP3 at the same bitrate.
Where you run into it: Game audio, Wikipedia and Wikimedia files, Spotify's streaming internals, Linux desktops.
What it costs you: Technical merit never bought it consumer support: plenty of car stereos and older phones simply do not list it.
M4A is an MPEG-4 container holding AAC audio — the same codec as a bare .aac file, wrapped so that players, tags and cover art all behave.
Where you run into it: iTunes and Apple Music purchases, voice memos, Zoom and Teams recordings, most phone-recorded audio.
What it costs you: Outside Apple's ecosystem support is good but not universal, and a few older tools still refuse the extension on sight.
This is a transcode between two lossy formats, so it is a second generation: OGG already discarded detail to get small, and M4A now encodes what is left and discards a little more. On a 320 kbps source you are unlikely to hear it. On something already thin — a voice note, a 96 kbps download — you may. Convert from the best copy you have, never from a copy of a copy.
Yes, entirely, and there is no cap on how many files you convert. No account, no watermark, no trial.
A little, in principle. OGG is already a lossy format and M4A is another one, so the audio is encoded a second time and a small amount more is discarded. From a good source it is very hard to hear; from an already-thin file it can be audible. Always convert from the best copy you have.
Roughly comparable, depending on the quality you pick. At the same bitrate the two files land within a few percent of each other; drop the bitrate and the M4A gets proportionally smaller.
Yes — M4A is one of the formats this converter writes, so the reverse page exists at /m4a-to-ogg/. Remember that going back and forth between two lossy formats degrades the audio a little each time.
The file is uploaded to do the conversion — nothing here runs in your browser — and both your upload and the converted result are deleted the moment the file is sent back. Nothing is stored and nothing is logged beyond the request itself.