WMA to AMR Converter

How to Convert WMA to AMR Online

1. Upload Your WMA File: Drag and drop your .wma files or click "Add Files" to pick them. Batch is supported, so queue several recordings or voice memos at once.
2. Pick Quality Preset: Default is Highest, which targets the top AMR-NB mode (12.2 kbit/s) — the same rate GSM full-rate (GSM-FR) replaced for toll-quality voice. Drop to Medium or Low (around 7.4 or 5.9 kbit/s) for smaller voicemail-style files; pick Lowest (4.75 kbit/s) only for the most aggressive size cut.
3. Set Audio Channel and Sample Rate (Optional): AMR-NB is mono-only, so the converter forces Audio Channel to Mono and Audio Sample Rate to 8000 Hz by default. Leave these as-is — AMR decoders reject stereo or non-8 kHz input. If your source is a stereo WMA, the channels are downmixed automatically.
4. Trim and Convert: Use the Trim control (HH:MM:SS.sss) to clip a ringtone-length section from a longer WMA before encoding, then click Convert. The .amr file downloads in seconds. No sign-up, no watermark, no install.

Why Convert WMA to AMR?

WMA (Windows Media Audio) is Microsoft's proprietary audio family, released August 17, 1999, and wrapped in the ASF container. It plays well on Windows but lacks native support on iOS, modern Android, and macOS without third-party players. AMR (Adaptive Multi-Rate) is the 3GPP speech codec adopted in October 1999 (3GPP TS 26.090) and was for many years the default voice format on GSM and UMTS handsets. Converting WMA to AMR strips music-grade overhead and produces a tiny mono file built specifically for speech.

• Feature-phone and legacy-handset playback — AMR-NB is the audio format every GSM-era Nokia, Sony Ericsson, and Samsung feature phone could decode without an app. WMA on those devices is a coin flip.
• Voicemail and IVR system input — telecom voicemail platforms and interactive voice response gateways often ingest AMR-NB at 8 kHz mono because that matches the bearer channel; uploading WMA forces a server-side transcode.
• Tiny voice-memo archives — at 4.75 kbit/s AMR-NB stores roughly 36 KB per minute of speech, versus around 240 KB per minute for a 32 kbit/s WMA Voice clip. Hour-long oral history archives shrink from megabytes to a couple hundred kilobytes per file.
• MMS attachments and 3GPP video audio tracks — the .amr extension and audio/amr MIME type are part of the 3GPP / 3GP container family, so AMR slots cleanly into MMS messages and 3GP video soundtracks.
• Push-to-talk and walkie-talkie apps — many low-bandwidth PTT systems still negotiate AMR-NB because it survives lossy mobile networks better than music codecs.
• Embedded systems and IoT voice prompts — microcontrollers with kilobytes of flash use AMR-NB for short spoken prompts (door entry systems, kiosks, automotive UI) where MP3 decoders are too heavy.

WMA vs AMR — Format Comparison

AMR-NB Bitrate Modes Quick Guide

AMR-NB defines exactly eight modes. Higher-bitrate modes give clearer voice; lower modes give the smallest files. The codec frames audio in 20 ms blocks of 160 samples regardless of mode.

For wider-bandwidth speech (50–7000 Hz) you would use AMR-WB at 6.6–23.85 kbit/s, but AMR-WB usually ships with the .awb extension; this converter targets standard AMR-NB .amr output.

Frequently Asked Questions

Why is my AMR file so much smaller than the original WMA?

Because AMR-NB throws away everything outside the 200–3400 Hz telephone band, downmixes to mono, and uses a 13-bit 8 kHz sampler — far less data than a 44.1 kHz stereo WMA. A three-minute WMA at 128 kbit/s is roughly 2.8 MB; the same clip as AMR-NB at 12.2 kbit/s is around 270 KB. That is a ~10x reduction, and most of it comes from discarding music-band frequencies a phone earpiece could not reproduce anyway.

Will AMR sound okay if my WMA is music?

No. AMR is a speech codec — it models the human vocal tract (ACELP) and assumes the input is a single voice. Music converted to AMR sounds harsh, washed-out, and full of warbling artefacts because cymbals, bass guitar, and harmony are outside the 3.4 kHz cutoff. For songs, convert to WMA to MP3 or WMA to AAC instead.

What's the difference between AMR-NB and AMR-WB?

AMR-NB (narrowband) covers 200–3400 Hz at 8 kHz sampling and 4.75–12.2 kbit/s — the classic GSM voice format. AMR-WB (wideband, also called G.722.2) covers 50–7000 Hz at 16 kHz sampling and 6.6–23.85 kbit/s, and powers HD Voice / VoLTE on modern networks. WB files usually use the .awb extension. This page outputs standard AMR-NB .amr, which is what feature phones and most "convert to AMR" workflows actually want.

Can iPhones play AMR files?

Yes. iMessage decodes AMR voice messages natively, and Voice Memos can play .amr attachments. The Files app and Music app are pickier, so for general iPhone playback (alarms, ringtones via GarageBand) most users prefer M4A — see WMA to M4A. AMR is the right choice when the receiving system specifically requires it.

Can I make a phone ringtone out of an AMR?

Older Symbian, Series 40, and BlackBerry handsets accept AMR ringtones directly — drop the file in the Ringtones folder and pick it. Modern iPhone ringtones must be M4R (renamed M4A under 30 seconds), and modern Android accepts AMR but most users use MP3 or OGG. If your target is an iPhone, convert WMA to M4A and rename, not AMR.

Why does the converter force Mono and 8000 Hz?

Because the AMR-NB bitstream syntax has no provision for stereo or any sample rate other than 8 kHz. Encoders that accept stereo input silently downmix; encoders that accept higher sample rates silently resample. We expose the controls so you can confirm the conversion path, but changing them away from Mono / 8000 Hz produces an out-of-spec file that most decoders will refuse.

Can I trim my WMA before converting to AMR?

Yes. The Trim control accepts HH:MM:SS.sss for both start time and duration, so you can clip a 20-second voicemail snippet or a 30-second ringtone section from a longer WMA without a separate edit pass. For more granular cutting (fade in/out, multi-segment), use the dedicated Audio Cutter.

How does AMR compare to Opus or Speex for voice?

Opus at 12 kbit/s wideband sounds dramatically better than AMR-NB at 12.2 kbit/s — Opus is the modern WebRTC choice. AMR's value today is interoperability: feature phones, MMS gateways, voicemail systems, and 3GP video soundtracks all assume AMR. If both endpoints are modern, prefer Opus or AMR to MP3 for archival; if the endpoint is 2007-era hardware or a telco system, AMR is still the right answer.

Is the conversion lossless?

No, both WMA Standard and AMR-NB are lossy codecs, so converting between them is a transcode — quality drops at every step. If you need a lossless intermediate (e.g., for archival before a final AMR encode), convert through WMA to WAV first, edit the WAV, then encode the WAV to AMR. That avoids cascading compression artefacts from the WMA decoder.