All about AMR files

AMR stands for Adaptive Multi-Rate and is an audio format that was developed specifically for voice recordings. The codec was originally developed by the ETSI (European Telecommunications Standards Institute) for GSM mobile networks and adopted as the standard voice codec by 3GPP in 1999.

AMR is narrowband and processes frequencies from 200 to 3400 Hz. This is well suited for human speech but not for music. The special feature: as the name implies, AMR can dynamically adjust its bit rate to network conditions. Depending on the connection quality, one of eight levels between 4.75 and 12.2 kbit/s can be selected.

Android, older iOS devices and virtually all earlier 3G mobile phones use AMR as the file format for voice recordings. .amr is also used in MMS voice messages and some VoIP apps.

AMR files can be opened with VLC, for example. For best compatibility, conversion to MP3 or AAC is optimal.

Last updated on 11. March 2026 by Sören with the experience of more than 127,898,006 converted files since 2013.