Use our free online converter to encode your audio files into the efficient AAC (Advanced Audio Coding) format. Convert from popular formats like MP3, WAV, FLAC, WMA, OGG, or extract audio from video files directly to AAC. This service is fast, free, secure (files deleted automatically), requires no signup, and accepts files up to 50 MB. Our converter writes AAC-LC at 192 kbps as a raw ADTS .aac file, keeping the source sample rate and up to 5.1 channels.
Creating AAC audio files is straightforward with our tool:
AAC is chosen in the 'Convert to:' dropdown menu.AAC (Advanced Audio Coding) is a lossy audio compression standard designed to be the successor to the MP3 format. It generally achieves better sound quality than MP3 at similar bitrates, meaning you can get smaller file sizes for the same perceived audio quality.
AAC is the standard or default audio format for YouTube, iPhone, iPod, iPad, iTunes, Nintendo DSi, Nintendo 3DS, DivX Plus Web Player, PlayStation 3, and various Nokia and Sony Ericsson mobile phones. It's often contained within .aac files, but is also commonly found inside .m4a, .mp4, and .3gp container files.
AAC files (and M4A/MP4 files containing AAC audio) are supported by a vast range of modern software and hardware:
You typically won't need extra software to play AAC files on current devices.
| Full name | Advanced Audio Coding (ADTS stream) |
|---|---|
| Compression | Lossy |
| Developed by | MPEG (Fraunhofer, Dolby, Sony, Nokia and others) |
| Introduced | 1997 |
| File extension | .aac |
| Typically used for | Streaming, broadcast, audio from recorders and apps |
| Plays on | iPhone, Android, modern browsers and most media players |
| Our output | AAC-LC, 192 kbps, raw ADTS stream |
We encode AAC-LC, the most compatible AAC profile, at 192 kbps and save it as a raw ADTS stream with the .aac extension. The sample rate is kept from your source, and so are the channels, up to 5.1 surround. There is no bitrate option, so every AAC file uses these settings.
Both can hold the same AAC audio. An .aac file is a bare ADTS stream with no container, so it has little room for tags and some players seek in it less accurately. An .m4a file wraps AAC in the MP4 container, which supports metadata and cover art. Pick M4A for music libraries and AAC when a tool specifically asks for .aac.
AAC is the more efficient codec, and its advantage is clearest at lower bitrates. At 192 kbps both AAC and MP3 sound very good for most listeners, and the files are the same size, about 1.44 MB per minute. AAC is a good choice if your devices support it; MP3 is still more universal on older hardware.
Android phones, Windows 10 and 11, VLC and most modern media players play .aac files. iPhones can play them, but Apple's Music app handles .m4a better than raw .aac, so M4A is usually the better choice for an Apple library. Some older car stereos and portable players read AAC only inside M4A files.
Yes, up to 5.1 channels are kept. Keep in mind that the 192 kbps bitrate is shared across all channels, so a 5.1 track has less data per channel than a stereo one. Stereo and mono sources stay stereo and mono.
It is re-encoded. The converter decodes the audio track and encodes it again as 192 kbps AAC-LC, so there is a small generation loss that is usually inaudible. The video track is discarded, and if the file has several audio tracks the default one is used. Files up to 50 MB can be uploaded.
Need detailed information or want to set a different default format? Visit our specific converter pages: