AAC → AMR

Yes, and it is worth planning around. Both formats are lossy, so the AMR encoder is working from audio that has already been through one psychoacoustic pass, and its own decisions compound the first set. At 192 kbps or above the result is still transparent for most listening. If you have a lossless master anywhere, encoding the AMR from that instead avoids the double pass entirely. AAC is lossy but more efficient than MP3, and it handles up to 48 channels natively rather than being bolted onto a stereo design. AMR is a narrowband speech codec running between 4.75 and 12.2 kbps, modelling the human vocal tract rather than the full audio spectrum.

Not intact. AAC carries a proper metadata block, but AMR has no standard place for artist, album, track number or cover art, so tags are dropped rather than mangled. Keep the AAC as the tagged copy, or re-tag afterwards with a tool like Mp3tag or MusicBrainz Picard. AMR destroys music: its 8 kHz bandwidth removes everything above telephone frequencies, and no amount of re-encoding brings it back.

Because one side of it is a speech codec rather than a music codec. It models the human vocal tract and discards everything outside telephone bandwidth, which is fine for a voice memo and destructive for anything with instruments in it. Converting away from it cannot restore the missing frequencies — they were never encoded in the first place. AAC is patent-encumbered, and a handful of very old players still refuse it where they would accept an MP3.

If AAC is lossy and AMR is lossless (e.g. MP3 → WAV), the AMR is no better than the AAC — you cannot recover information already discarded. If AAC is lossless and AMR is lossy, the AMR codec recompresses; at 192 kbps the result is transparent for most content.

Several files in one job need a paid plan. Free use is one file per conversion, one conversion an hour. On a paid plan you can add several files to one job, then download each result on its own or all of them in one ZIP.

By default yes — 48 kHz AAC stays 48 kHz in AMR. If you need to downsample for compatibility (96 kHz → 44.1 kHz for CD burning), the sample-rate option applies high-quality resampling in the same encode pass.

Not in this step. The converter has no loudness setting and leaves the level as it is. To even out the volume, run the finished AMR through a Normalize tool on this site.

MP3 plays almost everywhere. AAC plays on Apple devices, most Android phones and Sonos. FLAC plays on Sonos and Android but not on older iPods, and WAV plays on nearly everything but makes large files. There are no device presets on this page, so choose the target format your player supports. AMR makes voice recordings absurdly small — an hour of speech fits in a few megabytes — and it is what many phones still record calls in.

Yes. Uploaded AAC files are processed on our own conversion servers, no person reviews them, and they are never shared. The upload and the converted AMR are both deleted automatically about 24 hours after the conversion, which leaves time to download the result. See /privacy/ for the full policy.