CONVERT
AMR → WMA
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Fast, secure AMR to WMA conversion. No registration required.
Here is the short version — AMR is the narrowband speech codec built for mobile voice recordings and 3G calls. Hence the need for WMA. Moving audio from AMR into WMA is a routine job for podcasters, musicians, transcribers and anyone who needs a file to play somewhere the original would not. KaijuConverter reads the AMR once, re-encodes through FFmpeg at the bitrate you choose, and returns a polished WMA in seconds. Context: AMR is the narrowband speech codec built for mobile voice recordings and 3G calls. WMA is Microsoft's proprietary audio codec, historically tied to Windows Media Player.
AMR Audio
Source formatAMR (Adaptive Multi-Rate) is an audio format optimized for speech, used in phone calls.
Windows Media Audio
Target formatWMA is a proprietary Microsoft audio format from the Windows Media framework. Once common in the Windows ecosystem, it has been largely replaced by AAC and MP3 for general use.
Why convert AMR to WMA
The motivation for a AMR → WMA conversion is almost always practical: a playback device, hosting platform or editing suite that insists on WMA. The audio quality trade-off is controllable via bitrate; the compatibility win is immediate and unambiguous.
HOW TO CONVERT
AMR → WMA
Give us the AMR
Select a AMR (or several for batch). We read the header to pick decoder settings automatically.
Re-encode to WMA
The audio is decoded, optionally resampled, and re-encoded as WMA at transparent default bitrate.
Retrieve your WMA
Grab the download as soon as it is ready. Typical jobs finish in seconds for short clips.
Common Use Cases
Share across platforms
Send WMA files to anyone without worrying about whether they have the right software for AMR.
Embed in documents
Drop WMA output into Word, Google Docs, PowerPoint, Notion or a website without conversion warnings.
Optimize size
WMA often produces smaller files than AMR for web, email and storage.
Archive & future-proof
Store in a widely-supported format that will still open on future operating systems without legacy plugins.
AMR vs WMA — Strengths and limitations
What each format does best, and where it falls short.
AMR Strengths
- Extremely low bitrate — 4.75-12.2 kbps for speech.
- Designed for error-prone mobile channels — handles packet loss gracefully.
- Tiny file sizes — hours of voice in a few MB.
- Mandatory codec in all 3G/UMTS phones — universal cellular compatibility.
Limitations
- Speech-only — music sounds distorted.
- Narrowband (8 kHz sample rate) — muffled compared to modern codecs.
- Patent-encumbered until recently — licensing fees slowed adoption outside telephony.
WMA Strengths
- Good quality at low bitrates (32-64 kbps) — outperformed MP3 in that range.
- Native playback on every Windows version 2000 through 10.
- Lossless variant available (WMA Lossless) for archiving.
- Supports multichannel 5.1 surround audio.
Limitations
- Proprietary — poor support outside Windows and Windows Media Player.
- DRM variants made files brittle — many purchased tracks became unplayable when stores shut down.
- Ecosystem abandoned — no modern editors, hardware decoders, or streaming services use WMA.
AMR vs WMA — Technical specifications
Side-by-side comparison of the technical details.
AMR
- MIME type
- audio/amr
- Extensions
- .amr, .3ga
- Standard
- 3GPP TS 26.071 (narrowband), TS 26.171 (wideband)
- Sample rate
- 8 kHz (AMR-NB); 16 kHz (AMR-WB)
- Bitrates
- 4.75, 5.15, 5.9, 6.7, 7.4, 7.95, 10.2, 12.2 kbps
WMA
- MIME type
- audio/x-ms-wma
- Extension
- .wma
- Container
- ASF (Advanced Systems Format)
- Variants
- WMA Standard, WMA Pro, WMA Lossless, WMA Voice
- Max bitrate
- 768 kbps (WMA Pro)
| Specification | AMR | WMA |
|---|---|---|
| MIME type | audio/amr | audio/x-ms-wma |
| Extensions | .amr, .3ga | — |
| Standard | 3GPP TS 26.071 (narrowband), TS 26.171 (wideband) | — |
| Sample rate | 8 kHz (AMR-NB); 16 kHz (AMR-WB) | — |
| Bitrates | 4.75, 5.15, 5.9, 6.7, 7.4, 7.95, 10.2, 12.2 kbps | — |
| Extension | — | .wma |
| Container | — | ASF (Advanced Systems Format) |
| Variants | — | WMA Standard, WMA Pro, WMA Lossless, WMA Voice |
| Max bitrate | — | 768 kbps (WMA Pro) |
AMR vs WMA — Typical file sizes
Approximate file sizes for common scenarios.
AMR
- 1-min voice memo 45-90 KB
- 1-hour voicemail archive 3-5 MB
WMA
- 3-min song (128 kbps) 3 MB
- 3-min song (Lossless) 25-35 MB
- 1-hour talk (64 kbps) 28 MB
Quality & Compatibility
The WMA output is as good as the AMR source allows. If the AMR was encoded at 96 kbps, the WMA cannot reconstruct detail the encoder already dropped; picking a very high WMA bitrate just produces a larger file. Match WMA bitrate to the AMR quality for the best balance.
Tips for Best Results
- Sample-rate mismatches between AMR and target device (48 kHz phone output from a 44.1 kHz track) are handled automatically; no manual resampling needed.
- For audiobook delivery, match the platform spec exactly — ACX requires 192 kbps CBR 44.1 kHz stereo, for example.
- Batch-convert an album in one job so every track shares identical encoder settings and loudness normalisation.
Frequently Asked Questions
Lossy-to-lossy conversions (most combinations) re-compress the audio, which technically introduces some loss. At a 192 kbps or higher target it is inaudible on normal equipment. Lossy-to-lossless conversions freeze the existing quality but cannot improve it; lossless-to-lossy transcodes are only as good as the target bitrate you choose.
For voice content (podcasts, audiobooks, lectures) 128 kbps is indistinguishable from higher bitrates. For music, 192-256 kbps covers most listening; 320 kbps is the ceiling for WMA and the right choice for audio you plan to edit further. Above that, prefer a lossless target instead.
Yes. Title, artist, album, year and cover art travel from the AMR container to the WMA container automatically where both formats support them. If a tag field has no WMA equivalent, it is dropped silently. Use any tag editor (Mp3tag, MusicBrainz Picard) to fine-tune afterwards.
Related comparisons
See these formats side by side to understand which fits your use case best.
Related Guides
WMA Files: Windows Media Audio Format, Variants, DRM, and Conversion
Complete guide to WMA (Windows Media Audio) files — Standard/Pro/Lossless/Voice variants, DRM issues, player compatibility, FFmpeg conversion to MP3/AAC/FLAC/Opus, and batch conversion.
Read guideAMR Audio Format: The Mobile Voice Recording Standard Explained
Learn what AMR audio is, its history as a 3GPP/GSM codec, AMR-NB vs AMR-WB differences, and how to convert AMR voice recordings to MP3, WAV, or AAC using FFmpeg.
Read guideWMA (Windows Media Audio) Format: The Complete Guide
Complete guide to WMA audio: WMA Standard, Pro, Lossless and Voice variants, DRM lock issues, how to play WMA on Mac/Linux/Android, and FFmpeg conversion commands.
Read guideSecure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 60 minutes. We never read, share, or store your data.