How do I convert AMR to M4A?

Add your AMR 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

AMR to M4A Converter

Turn AMR files into M4A in a couple of clicks. Narrowband speech codec from mobile voice recordings. 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

AMR files (.amr) · up to 300 MB each

or paste files from your clipboard

Ready when you are

Drop a AMR 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 AMR 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.

AMR and M4A explained

AMR is a narrowband speech codec designed for mobile phone calls. It is optimised specifically for the frequency range of the human voice and sounds poor for anything else.

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 AMR files come from: Voice memos and voicemail from older phones.
Where M4A is used: iTunes purchases, Apple Music downloads, voice memos and audiobooks.

AMR vs M4A

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

AMR compared with M4A
Property	Source	Target
Compression	Lossy	Lossy or lossless
Introduced	1999	2001
Browser support	Poor. Convert to MP3 or WAV to use it.	Very good, especially on Apple platforms.

AMR is stronger at: Extremely small files. Adequate for speech intelligibility.
M4A is stronger at: Excellent quality per byte. Proper chapter support, which is why audiobooks use it. Strong metadata and artwork handling.

Why convert AMR to M4A?

People make this switch when they run into the limits of AMR: always — convert to MP3 or WAV so the recording stays usable. M4A is the better fit when apple ecosystem, audiobooks, or podcasts with chapters.

AMR limitations that prompt the switch: Terrible for music. Very limited playback support. Low sample rate ceiling.
What you give up: Less universal than MP3 on older or cheaper hardware. The extension hides what codec is actually inside.

Does converting AMR 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.