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AMR to M4A converter

Convert AMR to M4A in your browser. No upload and no account: the file never leaves your device, so the only size limit is your device’s memory.

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Other ways to convert AMR

Convert other formats to M4A

Read more about the AMR format and the M4A format, or see every audio tool and all audio conversions.

Should you convert AMR to M4A?

Fine when a player or app needs M4A. Converting between two lossy formats compresses the sound a second time, so match or exceed the original bitrate to keep the loss inaudible.

M4A also plays in more places: Apple devices, Android, browsers and most players; some older car stereos, Windows apps and forms refuse it.

AMR is narrow-band speech audio from phones and call recorders; M4A is AAC audio in an MP4 container, Apple’s everyday audio format. Use M4A for music and recordings on Apple devices, or anywhere AAC is accepted and size matters.

AMR and M4A compared
Property AMR M4A
Compression Lossy Lossy
Typical quality 4.75–12.2 kbps, 8 kHz 128–256 kbps AAC
Support A legacy format Opens almost everywhere
Best for Nothing today; convert old call recordings and voice memos Good-sounding audio at small sizes
Introduced 1999 2003

How to convert AMR to M4A

  1. 01

    Add your AMR

    Drop your AMR file onto the box, or click to choose it. It is read from your disk and stays there.

  2. 02

    Check the settings

    The output is already set to M4A. Change the bitrate if you want to; the defaults suit most files.

  3. 03

    Save the M4A

    Press convert and save the M4A. Several files come back together as a ZIP.

What changes when AMR becomes M4A

Two rounds of compression

Each lossy encode throws away a little more. A AMR at 128 kbps converted to M4A at 192 kbps sounds like the original; converted at 96 kbps it can turn swirly and dull.

Phone-quality sources stay phone quality

AMR recordings are usually sampled at 8 kHz for speech. Converting to M4A makes them play anywhere, but can’t add clarity that was never recorded.

A one-time engine download

AMR is decoded by FFmpeg compiled to WebAssembly, a 31 MB download the first time. After that it is cached, and the conversion never leaves your device.

Expect a much larger file

M4A is far bigger for the same content. Choose it because something needs M4A, not to send or store the file. AMR: About 90 KB a minute. M4A: About 1 MB a minute at 128 kbps.

This page is put together from our notes on each format, choosing only what is true of AMR and M4A, so every pairing states the same facts the same way. How these pages are made.

Why it doesn’t upload

Recordings are often private: interviews, voice notes, unreleased music. Your browser can decode and encode audio itself, so there is no reason to send it anywhere.

How to check for yourself

Worth knowing

  • About the AMR. AMR is sampled at 8 kHz, so converting it to a high-quality format won’t add any clarity; it will still sound like a phone call.
  • About the M4A. An .m4a can also hold lossless ALAC audio, several times larger; the extension alone doesn’t tell you which.
  • MP3, WAV, M4A, OGG, Opus and FLAC are converted by your browser directly. WMA, AMR, APE, AC3 and the other specialist formats use the FFmpeg engine, a one-time 31 MB download.

Questions

Does converting AMR to M4A lose quality?

M4A is lossy, so a little is discarded, but at the default bitrate the difference is inaudible for nearly everyone.

Will an M4A play in my car or on my phone?

M4A opens almost everywhere: Apple devices, Android, browsers and most players; some older car stereos, Windows apps and forms refuse it.

Read more about this

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