M4A to CAF Converter

What happens when you convert M4A to CAF

• The audio is decoded and written as Apple Lossless (ALAC) in a Core Audio Format file.
• The CAF holds Apple Lossless, which GarageBand, Logic Pro, QuickTime Player and Apple's own afconvert read. AAC inside a CAF, which some iOS apps use for short sounds, is not written here.

How to convert M4A to CAF online

1. Press "Choose M4A files" and select one or more files, or drag them onto the box. You can add files of any size your device can hold in memory.
2. Adjust the settings if you need to: the bitrate controls quality and size. The defaults suit most people.
3. Press "Convert to CAF". The first audio or video conversion downloads the converter engine, about 32 MB, which your browser then keeps for next time.
4. Save each CAF with its download button. Close the tab and every trace of the files is gone from memory.

Why convert M4A to CAF?

M4A files usually come from iTunes purchases, iPhone voice memos and Apple Music downloads. People convert them to CAF because CAF is Apple's own audio format for GarageBand, Logic Pro and sounds inside iPhone and Mac apps, with no limit on file size.

In short, M4A is good at what it was made for, and CAF is the more practical choice when the file has to play on another device or app. M4A plays in all current browsers and every Apple device, while CAF plays in Safari and Apple apps; not in Chrome or Firefox.

How to convert M4A to CAF on Windows, Mac, iPhone and Android

On Windows

Open this page in Chrome, Edge or Firefox, drag your M4A files in from File Explorer, and press Convert. Each CAF is saved to your Downloads folder. If you prefer a desktop program, VLC can also convert M4A to CAF: choose Media, then Convert / Save.

On a Mac

Safari, Chrome and Firefox all work. Drag the M4A files from Finder onto the drop zone and the CAF files land in Downloads.

On iPhone and iPad

Open the page in Safari and tap Choose M4A files. You can pick from Photos or from the Files app. The converted CAF appears in Files, in the Downloads folder.

On Android

Open the page in Chrome, tap Choose M4A files and pick them from Files or your gallery. The CAF is saved to the Download folder, where any file manager can find it. Keep the screen on while a long video converts, because Android may pause a tab in the background.

Best settings for M4A to CAF

CAF is lossless, so there is no quality setting: every sample of the decoded M4A is kept. What changes is size. CD-quality stereo, 44.1 kHz at 16 bits, takes about 10 MB per minute as uncompressed PCM.

The M4A is lossless too, so the conversion is exact in both directions.

M4A vs CAF: the differences

About M4A and CAF files

What is an M4A file?

M4A is an MP4 file that only holds audio, which is why renaming one to .mp4 often works. Voice Memos on iPhone saves recordings as M4A.

What is a CAF file?

CAF is Apple's container with no practical size limit, while WAV and AIFF stop at 4 GB. It shows up mostly in iOS development and GarageBand projects.

M4A to CAF not working? Common problems

• The conversion is slow. Audio and container changes take seconds, but re-encoding video runs on your own processor. Lower the resolution to 720p, close other tabs, and keep the device plugged in.
• The tab stops or reloads on a very large file. Browsers limit how much memory one tab can use, around 2 GB and less on phones. Split long recordings or convert them on a computer.
• Song titles are missing. Tags such as title and artist are copied when CAF can store them, but cover art is not carried over.

Convert M4A to CAF with ffmpeg

This converter runs ffmpeg inside your browser. If you would rather use the ffmpeg command line on your own computer, this command produces an equivalent CAF with the same kind of settings:

ffmpeg -i input.m4a -vn -c:a alac -f caf output.caf

Replace input.m4a with the name of your file. For a whole folder of M4A files, run the command in a loop, or drop them all on the converter above, which processes them one after another.