Convert WMA to AMR — Free Online Converter

WMA is Microsoft's audio codec delivering compressed audio typically at 64-320 kbps. AMR (Adaptive Multi-Rate) is a speech-optimized codec created by ETSI for GSM and UMTS mobile voice calls. AMR-NB operates at 8 kHz with bitrates from 4.75 to 12.2 kbps, while AMR-WB extends to 16 kHz at up to 23.85 kbps.

Converting WMA to AMR re-encodes the audio through a speech-optimized codec, dramatically reducing file size while maintaining intelligible voice reproduction. This conversion is specifically designed for speech content — AMR handles music poorly but excels at clear voice at minimal bitrates.

AMR is the native codec for billions of mobile phones and the backbone of GSM voice infrastructure. Telecom voicemail systems, IVR platforms, and MMS gateways often require AMR input. If you have WMA voice recordings from a Windows-based system that need to enter the mobile telephony pipeline, AMR conversion is required.

The extreme compression (128 kbps WMA to 12.2 kbps AMR-NB) makes AMR ideal for mass archival of voice content. Call center recordings, dictation files, and interview archives stored as WMA can be compressed further for long-term storage.