CAF to MP3 Converter
Core Audio Format is Apple's in-house container, and outside a Mac or an iPhone almost nothing opens it. Convert the .caf to MP3 and the same sound plays on a Windows laptop, an Android phone, a car stereo or a web upload form.
Audio Converter
or drop MP3, WAV, M4A … files here ·
Max 95 MB per file· Up to 20 files· Deleted after 30 minutes
Files are processed on our servers and deleted after 30 minutes.
Constant bitrate (CBR) gives a predictable size and works on every player. Variable bitrate (VBR) spends bits where the music needs them and is usually smaller at the same quality.
Keep the source rate unless a device asks for one. 44.1 kHz is CD standard, 48 kHz is video standard, 8 kHz is used by phone systems and AMR.
Mono halves the size of lossless files and is fine for voice recordings.
16-bit is CD quality. 24-bit keeps headroom for editing and mastering; converting a 16-bit source up does not add detail.
Optional. Seconds (e.g. 75) or minutes:seconds (1:15). Leave empty to start at the beginning.
Optional. Same format as the start time. Leave empty to keep everything up to the end.
How to use this tool
- 1
Upload the .caf files
Add up to 20 files of up to 95 MB each. It does not matter which codec is inside, PCM, AAC, Apple Lossless or Opus; each is decoded before encoding.
- 2
Choose a bitrate
Bitrate is 192 kbps, a good fit for music and loops. A voice message sounds the same at 128 kbps or even 96 kbps and takes much less space.
- 3
Convert to MP3
Press Convert to MP3 and download each file, or all of them as one ZIP. Nothing needs installing and no account is needed.
What a CAF file is and why other devices refuse it
Apple introduced the Core Audio Format with Mac OS X 10.4 Tiger in 2005 to fix two limits of AIFF and WAV: their 32-bit size fields, which cap a file at 4 GB, and the need for a separate format per codec. A .caf file uses 64-bit sizes and can wrap almost any codec Core Audio knows, from plain PCM to AAC, Apple Lossless and Opus. That flexibility suits Apple's own apps, and it is why iOS developers ship short app sounds as CAF.
Microsoft never adopted it, Android has no CAF support, and browsers do not play it. The extension tells another system nothing about the codec inside, so even software that understands AAC or PCM usually stops at the container. If you are curious what is inside before converting, macOS ships a small command for that.
afinfo ~/Desktop/Audio\ Message.caf
CAF to MP3 converter: what the numbers mean
- CAF arrives with Mac OS X 10.4 Tiger
- 2005
- chunk sizes, so no 4 GB ceiling
- 64-bit
- about one minute of MP3 at 192 kbps
- 1.4 MB
- files per batch on this page
- 20
The size of the MP3 depends only on the bitrate and the length, not on what the CAF contained. One minute at 192 kbps is about 1.4 MB; at 128 kbps it is about 0.96 MB. A minute of 16-bit stereo PCM inside a CAF is around 10 MB, so music loops shrink a lot, while a voice message that was already AAC may barely change size.
Converting a lossy CAF, such as an AAC voice memo, to MP3 adds a second round of compression. At 128 kbps or more that is inaudible for speech. For music already stored as AAC, keep the bitrate at 192 kbps or higher. Tags written by Apple apps, such as a loop's name, are copied where MP3 has a matching field when Keep tags and cover art is on. Apple's own M4A to MP3 route covers voice memos saved as .m4a.
CAF and MP3 compared
CAF
Core Audio Format
CAF is Apple's Core Audio Format, introduced with Mac OS X 10.4 in 2005. It can hold many codecs, including PCM, AAC, ALAC and Opus, and has no practical file-size limit, unlike WAV and AIFF. It is used by iOS and macOS apps, Logic Pro, GarageBand and iPhone sound effects. Windows and Android software rarely supports CAF.
- Compression
- Lossy or lossless
- Transparency
- –
- Animation
- –
- Introduced
- 2005 · Apple
MP3
MP3 audio
MP3 (MPEG-1 Audio Layer III) is a lossy audio format developed largely at the Fraunhofer Institute and standardised by MPEG in 1993. It removes sounds the ear is unlikely to notice, shrinking music to about a tenth of CD size at 128–320 kbps. All patents have expired, and every phone, car stereo, browser and media player supports it. Quality loss is audible at low bitrates and accumulates with re-encoding.
- Compression
- Lossy
- Transparency
- –
- Animation
- –
- Introduced
- 1993 · Fraunhofer IIS / MPEG
CAF is native to Apple's audio frameworks, so voice messages, loops and app sounds saved on a Mac arrive in a container Windows, Android and web forms do not recognize; MP3 hands the same recording to every device without asking anyone to install software.
CAF to MP3 questions
Where do .caf files usually come from?
The most common sources are audio messages saved from the Messages app on a Mac, Apple Loops from GarageBand and Logic Pro, sound effects pulled out of iOS and macOS apps, and files made with Apple's afconvert command-line tool. All of them play in QuickTime Player on a Mac, which is why the problem often appears only when the file is sent to someone else.
Can Windows or Android play a CAF file at all?
Not with their built-in players. VLC can open many CAF files on both systems, but the person you send it to probably does not have it, and phone apps, browsers and upload forms reject the extension. MP3 removes the question entirely.
Where does a Mac keep iMessage audio messages?
Audio messages received on a Mac are saved as .caf files inside the Library/Messages/Attachments folder of your home folder. In Finder press Shift-Command-G, type ~/Library/Messages/Attachments, and search the subfolders for .caf. Upload it here and pick 96 or 128 kbps, since speech does not need more.
Can I use GarageBand's Apple Loops outside Apple software?
Technically yes, once they are MP3, and Apple's license lets you use the loops inside your own music. It does not let you hand the loops out as standalone sound files or sample packs, so convert them to build a track, not to share the loops themselves.
My CAF holds lossless audio. Should it still become MP3?
Only if the goal is a small file that plays everywhere. For editing on another platform, choose WAV under Convert to so nothing is thrown away; for a lossless archive, choose FLAC. The audio converter lists every target.
