Audio
What is an AMR file?
Updated Jul 2026
AMR (Adaptive Multi-Rate) is a compressed audio format built specifically for recording speech, not music. It's the default many Android phones and voice recorder apps use for calls, voicemail, and voice memos. It keeps files tiny by throwing away audio detail that doesn't matter for a voice, which is also why it sounds thin and won't open in most media players or on Apple devices.
- Extension
- .amr
- Type
- Audio
- Typically
- Voice recordings
- Compression
- Lossy
Why AMR exists
AMR was developed in the late 1990s as a speech codec for mobile networks and later standardized for 3G phones. It was designed to squeeze a phone call into as little data as possible, so carriers built it into the call and voicemail systems that still show up on Android phones today.
The codec works by focusing entirely on the frequency range of a human voice and adjusting its bit rate on the fly depending on how much detail a moment of speech needs. Anything outside that range, background music, a wide dynamic range, subtle detail, gets stripped out. That's fine for someone talking into a phone and rough for anything else.
Most people run into AMR through a voice memo app, a saved voicemail, or an old messaging app that recorded voice notes this way. The trouble starts when they try to share it, edit it, or play it on a computer or an iPhone, since a lot of software simply doesn't recognize the format without converting it first.
The trade-offs
Strengths
- Extremely small file size for spoken recordings
- Compresses well even over slow mobile connections
- Still the default for calls and voice memos on many Android phones
Watch-outs
- Sounds noticeably worse than MP3 or WAV, especially for anything besides speech
- Not supported by most media players or editing software without converting
- Doesn't play natively on iPhone or in iTunes
- Poor quality if you try to use it for music or ambient sound
A note on privacy
An AMR file doesn't usually carry location data the way a photo does, but the content itself can be sensitive: a voicemail, a personal voice memo, a recorded conversation. Uploading it to an online converter sends that recording to a stranger's server just to get an MP3 back. Converting it on your own computer keeps the actual audio, and whatever was said in it, on your machine.
Questions
How do I open an AMR file?
Many phones and media players don't open AMR directly. The simplest fix is converting it to MP3 or WAV, which almost everything can play.
Is AMR better than MP3?
No. AMR files are smaller, but MP3 sounds noticeably better for anything beyond plain speech. AMR only makes sense when file size matters more than quality.
Why does my phone save voice notes as AMR?
Android's built-in recorder and voicemail systems have long defaulted to AMR because it was designed for exactly that: cheap, low-bandwidth speech recording.
Can I play AMR on an iPhone?
Not natively. You'll need to convert it to a format like M4A or MP3 before it will play in the Voice Memos or Music apps.
Can I convert AMR without uploading it?
Yes. A desktop app like Morphjet converts AMR on your own computer, so the recording never leaves your machine.
Morphjet opens and converts AMR and 1,800+ other formats, all on your own computer. Launching this July.