Convert CAF to MP3 — Free Online Tool
Convert CAF audio files to MP3 using FFmpeg.wasm entirely in your browser — no upload required. This tool decodes your CAF file (which may contain PCM, AAC, FLAC, or other Apple-native codecs) and re-encodes it to MP3 using the LAME encoder, making your audio universally playable on any device or platform.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your CAF file here
or click to browse
Free — no uploads, no signups. Your files never leave your browser.
Settings
Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
CAF (Core Audio Format) is Apple's container format and can hold audio encoded in a variety of codecs including PCM, AAC, FLAC, Opus, and others. MP3 uses only the LAME encoder (libmp3lame), so regardless of what codec is inside the CAF container, FFmpeg must fully decode the source audio to raw PCM and then re-encode it as lossy MPEG Audio Layer III data. This means conversion always involves transcoding — there is no stream-copy shortcut available here. The resulting MP3 file will be significantly smaller than an uncompressed CAF, but some audio detail is permanently discarded during lossy compression. At 128k bitrate (the default), the output is suitable for general listening, podcasts, and web playback.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool. In this browser-based tool, FFmpeg runs locally via WebAssembly (FFmpeg.wasm) — your CAF file never leaves your device. |
-i input.caf
|
Specifies the input file as a CAF (Core Audio Format) container. FFmpeg will detect the internal codec automatically — whether it's PCM, AAC, FLAC, or another supported format — and decode it accordingly. |
-c:a libmp3lame
|
Selects the LAME MP3 encoder to encode the audio output. Since MP3 supports only this one encoder and CAF audio must always be transcoded (never stream-copied to MP3), this flag is required for every CAF-to-MP3 conversion. |
-b:a 128k
|
Sets the MP3 output bitrate to 128 kilobits per second, a widely accepted standard for general-purpose listening that balances file size and audio quality. Increase to 192k or 320k for better fidelity, or decrease to 96k or 64k for smaller files such as voice recordings or podcasts. |
output.mp3
|
Defines the output filename and tells FFmpeg to write the result as an MP3 file. The .mp3 extension also confirms to FFmpeg that the output container should be MPEG Audio Layer III, consistent with the libmp3lame encoder selected above. |
Common Use Cases
- Share Apple Voice Memo recordings (saved as CAF) with Android users, Windows PCs, or web platforms that don't support the CAF container
- Upload music or sound recordings captured on macOS or iOS to streaming platforms, social media sites, or podcast hosts that require MP3
- Reduce the file size of large uncompressed PCM-in-CAF recordings from professional audio software before distributing them as demos or samples
- Convert CAF sound effects or audio assets exported from Logic Pro or GarageBand into MP3 for use in cross-platform game engines or web projects
- Prepare Apple-recorded interview audio in CAF format for editing in non-Apple software like Audacity or Adobe Premiere that handles MP3 more universally
- Archive CAF recordings from older iOS apps in a future-proof, widely supported format that will remain playable without Apple ecosystem dependencies
Frequently Asked Questions
Yes — MP3 is a lossy format, so some audio detail is permanently discarded during encoding. If your CAF file contains uncompressed PCM audio (which is lossless), the quality loss will be noticeable compared to the source, especially at lower bitrates like 64k or 96k. At 128k or higher, most listeners won't notice the difference for speech or typical music. If your CAF already contains lossy AAC audio, converting to MP3 means transcoding from one lossy format to another, which compounds the quality loss — in that case, using the highest available bitrate (320k) is advisable.
CAF is a proprietary Apple container format designed primarily for macOS and iOS environments. It is not supported natively by most web browsers, Android devices, Windows media players, or non-Apple software. MP3, by contrast, is one of the most universally supported audio formats in existence and will play on virtually any device, browser, or platform without additional software. Converting to MP3 solves compatibility issues almost universally.
Replace the value after '-b:a' in the command with your desired bitrate. For example, use '-b:a 320k' for the highest MP3 quality, '-b:a 192k' for a good balance of size and quality, or '-b:a 96k' for smaller files where audio fidelity is less critical. Higher bitrates produce larger files but preserve more audio detail. For speech-only content like voice memos or podcasts, 96k or 128k is generally sufficient; for music, 192k or 320k is recommended.
The command shown converts a single file, but on your local desktop you can batch process using a shell loop. On macOS or Linux, run: 'for f in *.caf; do ffmpeg -i "$f" -c:a libmp3lame -b:a 128k "${f%.caf}.mp3"; done'. On Windows Command Prompt, use: 'for %f in (*.caf) do ffmpeg -i "%f" -c:a libmp3lame -b:a 128k "%~nf.mp3"'. The in-browser tool processes one file at a time.
CAF files store metadata using Apple's 'info chunks', while MP3 uses ID3 tags — these are different metadata systems. FFmpeg will attempt to map common fields like title, artist, and album during conversion, but non-standard Apple-specific metadata fields may not carry over. If your CAF file originated as a Voice Memo, it likely has minimal metadata to begin with. After conversion, you can edit the MP3's ID3 tags using tools like Mp3tag or your DAW of choice.
Yes. If your CAF contains AAC-encoded audio, FFmpeg must decode the AAC stream to PCM and then re-encode it as MP3. This is a lossy-to-lossy transcode, meaning each encoding step introduces its own compression artifacts. The final MP3 will have lower quality than either the original source audio or a freshly encoded AAC file at the same bitrate. To minimize this degradation, use the highest MP3 bitrate available (320k). If you need to retain the best quality, consider keeping the CAF or converting to a lossless format like FLAC instead.
Technical Notes
CAF is a flexible container that supports a wide range of audio codecs including PCM variants (16-bit, 24-bit, 32-bit, float), AAC, FLAC, Opus, Vorbis, and legacy telephony codecs like A-law and μ-law. MP3 supports only one encoder: libmp3lame. This means every CAF-to-MP3 conversion is a full transcode — the source audio is fully decoded regardless of its internal codec before being re-encoded. The default bitrate of 128k using libmp3lame produces a joint-stereo MP3 that is broadly compatible with all MP3 players, including very old hardware devices and car stereos. CAF supports high-resolution audio (e.g., 24-bit or 32-bit PCM at sample rates up to 192kHz), but MP3 is limited to a maximum sample rate of 48kHz and 16-bit effective depth, so high-resolution source material will be downsampled during conversion. If preserving high-resolution audio fidelity is important, consider converting to FLAC instead of MP3. CAF files can theoretically exceed 4GB (overcoming WAV and AIFF limits), so the 1GB browser processing limit may be relevant for long, uncompressed recordings.