How do I convert AAC to M4A?

Add your AAC file to the upload area above, then press Convert. The M4A file downloads straight to your device. You do not need an account, and there is no watermark.

Are my files uploaded to a server?

No. This conversion runs entirely inside your browser using WebAssembly, so the file never leaves your device — you can even disconnect from the internet after the page loads and it will still work.

Does converting to M4A reduce quality?

M4A uses lossy compression, so some data is discarded. At the default quality the difference is very hard to see or hear; raise the quality setting if you need to be certain, at the cost of a larger file.

How large a file can I convert?

Up to 300 MB per file for this conversion. Because the work happens in your browser, the practical limit is your device's memory — larger files work on a desktop with plenty of RAM and may fail on an older phone.

Can I convert several files at once?

Yes. Add as many as you like and press Convert All. Each file is processed independently, so one failure does not stop the rest, and you can download everything together as a ZIP.

Can I use this on my phone?

Yes. FileTools360 works in mobile browsers on iOS and Android, including choosing files straight from your camera roll. Very large videos may run out of memory on a phone — those are better converted on a laptop.

AudioAdjustable qualityRuns in your browser

AAC to M4A Converter

Turn AAC files into M4A in a couple of clicks. The successor to MP3 — better quality per bit. MP4 container holding AAC or ALAC audio. The output is re-encoded, so quality depends on the settings you choose.

On your deviceNever uploadedGone when you close the tabHow this works

Drop your files here

AAC files (.aac, .adts) · up to 300 MB each

or paste files from your clipboard

Ready when you are

Drop a AAC file above and FileTools360 will turn it into M4A — right here on your device, without uploading anything.

⌘K to search converters

How to use it

1
Add your AAC files
Drag them onto the upload area, choose them from your device, or paste them from your clipboard. You can queue several at once.
2
Adjust the settings if you want to
The defaults suit most people. Open Advanced to control bitrate, sample rate and channels and start and end times.
3
Convert and download
Press Convert. Everything happens on your own device — nothing is uploaded. Download files one by one, or grab them all as a ZIP.

AAC and M4A explained

AAC is the successor to MP3 and is the default audio codec for MP4 video, Apple Music and YouTube. At the same bitrate it generally sounds noticeably better than MP3.

M4A is an MP4 container holding only audio — usually AAC, sometimes Apple Lossless. The extension exists mainly so players know not to look for a video track.

Where AAC files come from: Streaming services, video soundtracks and Apple devices.
Where M4A is used: iTunes purchases, Apple Music downloads, voice memos and audiobooks.

AAC vs M4A

The two formats solve different problems, which is why converting between them involves trade-offs rather than a straight upgrade.

AAC compared with M4A
Property	Source	Target
Compression	Lossy	Lossy or lossless
Introduced	1997	2001
Browser support	Excellent across modern devices.	Very good, especially on Apple platforms.

AAC is stronger at: Better quality per bit than MP3. The standard audio track for MP4 video. Excellent device support.
M4A is stronger at: Excellent quality per byte. Proper chapter support, which is why audiobooks use it. Strong metadata and artwork handling.

Why convert AAC to M4A?

People make this switch when they run into the limits of AAC: archiving, or targeting very old playback hardware. M4A is the better fit when apple ecosystem, audiobooks, or podcasts with chapters.

AAC limitations that prompt the switch: Still lossy. Patent licensing applies to encoders. Slightly less universal than MP3 on very old hardware.
What you give up: Less universal than MP3 on older or cheaper hardware. The extension hides what codec is actually inside.

Does converting AAC to M4A reduce quality?

Both formats store the content without discarding data, so this conversion preserves it exactly. The file size may change because the two formats compress differently, but the content itself is unaffected.