How to Convert AMR to MP3: Fix Old Voice Recordings

What Are AMR Files and Why Do You Have Them?

If you have stumbled across a folder of .amr files on an old phone backup, a USB drive from 2012, or buried in a WhatsApp data export, you are not alone. AMR (Adaptive Multi-Rate) files are a relic of the mobile phone era before smartphones standardized on AAC and Opus — and they are surprisingly difficult to play on modern devices.

AMR was the dominant format for mobile voice recordings, voicemail systems, and MMS audio messages from roughly 2003 to 2015. Nokia, Samsung, Sony Ericsson, and most early Android phones used AMR as their default voice recorder format. Older versions of WhatsApp stored voice notes as AMR files. Many corporate voicemail systems still deliver messages in AMR format.

The problem is that AMR support on modern devices is inconsistent at best. Windows does not play AMR natively. macOS can sometimes handle it, sometimes not. Most music players and audio editors ignore AMR files entirely. If you want to listen to, share, or archive these recordings, you need to convert them to MP3 or another widely supported format.

This guide covers everything you need to know: what AMR actually is, how to convert it to MP3 with the best possible quality, how to handle batch conversion of large collections, and how to rescue audio quality from a format that was never designed for high fidelity.

Understanding AMR Audio

AMR Technical Specifications

Property	AMR-NB (Narrowband)	AMR-WB (Wideband)
Full Name	Adaptive Multi-Rate Narrowband	Adaptive Multi-Rate Wideband
File Extension	.amr	.awb or .amr
Sample Rate	8,000 Hz	16,000 Hz
Bitrate Range	4.75 - 12.2 kbps	6.6 - 23.85 kbps
Channels	Mono	Mono
Frequency Response	300 - 3,400 Hz	50 - 7,000 Hz
Compression	Lossy (ACELP)	Lossy (ACELP)
Primary Use	Voice calls, voicemail	HD Voice calls
Quality	Telephone quality	FM radio quality

The key thing to understand about AMR is that it was designed exclusively for voice at extremely low bitrates. At its most common setting (12.2 kbps for AMR-NB), the entire audio signal is compressed into about 1.5 kilobytes per second. For comparison, a low-quality MP3 at 64 kbps uses roughly 8 kilobytes per second — more than 5 times the data rate. AMR achieves this extreme compression by being optimized for the narrow frequency range of human speech and discarding everything else.

This means AMR files have an inherent quality ceiling. No amount of conversion can make an 8 kHz, 12.2 kbps AMR recording sound like a studio recording. But converting to MP3 makes the files playable everywhere and allows you to apply enhancements that improve clarity.

Where AMR Files Come From

• Old phone voice recorders: Nokia, Samsung, Sony Ericsson, LG, and early Android phones (pre-2015)
• WhatsApp voice notes: Older versions of WhatsApp stored voice messages as .amr files (newer versions use Opus)
• Voicemail systems: Many corporate and carrier voicemail systems deliver messages in AMR format
• MMS messages: Audio attachments in MMS messages were often AMR
• Old phone backups: iTunes, Samsung Kies, and Nokia PC Suite backups may contain AMR recordings
• Feature phones: Basic phones (non-smartphones) still use AMR for voice recording

Converting AMR to MP3

Basic Conversion with FFmpeg

# Simple AMR to MP3 conversion
ffmpeg -i recording.amr -c:a libmp3lame -b:a 128k -ar 44100 recording.mp3

# With quality optimization for voice
ffmpeg -i recording.amr -c:a libmp3lame -b:a 96k -ar 22050 -ac 1 recording.mp3

Since AMR source audio has a maximum frequency content of 3,400 Hz (narrowband) or 7,000 Hz (wideband), using a high sample rate like 44.1 kHz is technically unnecessary. The extra samples above the source's frequency ceiling contain silence. However, 44.1 kHz ensures maximum compatibility with all players and devices, and the file size difference for short recordings is negligible.

Optimized Conversion for Best Quality

# Enhanced conversion with noise reduction and normalization
ffmpeg -i recording.amr \
  -af "highpass=f=80,lowpass=f=4000,anlmdn=s=7:p=0.002:r=0.002,loudnorm=I=-16:TP=-1:LRA=11" \
  -c:a libmp3lame -b:a 128k -ar 44100 recording.mp3

This pipeline:

1. highpass=f=80: Removes low-frequency rumble below 80 Hz
2. lowpass=f=4000: Removes empty high-frequency content above 4 kHz (for AMR-NB)
3. anlmdn: Applies non-local means denoising to reduce background noise
4. loudnorm: Normalizes loudness to -16 LUFS for consistent volume

Using the Online Converter

If you do not want to install FFmpeg, our audio converter handles AMR to MP3 conversion directly in your browser:

1. Upload your AMR file (or drag and drop multiple files)
2. Select MP3 as the output format
3. Choose 128 kbps as the bitrate (higher is unnecessary for AMR source material)
4. Click Convert and download

For format-specific conversion pages, use the MP3 converter hub.

Batch Converting AMR Files

If you have a folder full of old voice recordings, batch conversion saves significant time.

Bash Script (macOS/Linux)

#!/bin/bash
# Convert all AMR files in a directory to MP3
for amr in /path/to/recordings/*.amr; do
  filename=$(basename "$amr" .amr)
  ffmpeg -i "$amr" \
    -af "highpass=f=80,loudnorm=I=-16:TP=-1:LRA=11" \
    -c:a libmp3lame -b:a 128k -ar 44100 \
    "/path/to/output/${filename}.mp3" -y
done
echo "Conversion complete!"

PowerShell Script (Windows)

# Convert all AMR files in a directory to MP3
Get-ChildItem -Path "C:\recordings" -Filter "*.amr" | ForEach-Object {
    $output = "C:\output\$($_.BaseName).mp3"
    ffmpeg -i $_.FullName -af "highpass=f=80,loudnorm=I=-16:TP=-1:LRA=11" -c:a libmp3lame -b:a 128k -ar 44100 $output -y
}

Preserving File Dates

AMR files from old phones often have meaningful creation dates (when the recording was made). By default, the converted MP3 will have today's date. To preserve the original timestamp:

#!/bin/bash
# Convert AMR to MP3 while preserving original file timestamps
for amr in /path/to/recordings/*.amr; do
  filename=$(basename "$amr" .amr)
  output="/path/to/output/${filename}.mp3"
  ffmpeg -i "$amr" -c:a libmp3lame -b:a 128k -ar 44100 "$output" -y
  # Copy the original file's modification timestamp
  touch -r "$amr" "$output"
done

For large batch operations, our batch processing guide covers additional optimization techniques.

Enhancing AMR Audio Quality

AMR recordings are inherently low quality, but several post-processing techniques can improve clarity and listenability.

Noise Reduction

Old phone recordings often have significant background noise — hiss, hum, wind noise, or ambient sounds:

# Aggressive noise reduction for very noisy recordings
ffmpeg -i recording.amr \
  -af "anlmdn=s=10:p=0.003:r=0.003,highpass=f=100,lowpass=f=3500" \
  -c:a libmp3lame -b:a 128k recording.mp3

The anlmdn filter uses non-local means denoising, which is effective at removing steady-state noise (hiss, hum) without distorting the voice. The s parameter controls strength — higher values remove more noise but can introduce artifacts.

Volume Normalization and Compression

Many AMR recordings have extreme volume variations — the speaker moves closer and further from the phone's microphone:

# Compress dynamics and normalize
ffmpeg -i recording.amr \
  -af "acompressor=threshold=-20dB:ratio=4:attack=10:release=200,loudnorm=I=-16:TP=-1:LRA=7" \
  -c:a libmp3lame -b:a 128k recording.mp3

Equalization for Speech Clarity

Boosting the frequencies most important for speech intelligibility can improve clarity:

# Speech clarity EQ: boost presence (2-4 kHz) and cut mud (200-400 Hz)
ffmpeg -i recording.amr \
  -af "equalizer=f=300:t=q:w=1:g=-3,equalizer=f=3000:t=q:w=1:g=4,loudnorm=I=-16:TP=-1" \
  -c:a libmp3lame -b:a 128k recording.mp3

Full Enhancement Pipeline

Combining all enhancements for maximum clarity:

ffmpeg -i recording.amr \
  -af "highpass=f=80,\
       lowpass=f=4000,\
       anlmdn=s=7:p=0.002:r=0.002,\
       equalizer=f=300:t=q:w=1:g=-3,\
       equalizer=f=2500:t=q:w=1.5:g=4,\
       acompressor=threshold=-20dB:ratio=3:attack=10:release=200,\
       loudnorm=I=-16:TP=-1:LRA=7" \
  -c:a libmp3lame -b:a 128k -ar 44100 enhanced.mp3

Recovering AMR Files from Old Devices

From WhatsApp Backups

WhatsApp voice notes are stored in:

• Android: /sdcard/WhatsApp/Media/WhatsApp Voice Notes/
• iPhone: Within the WhatsApp backup (requires extraction tool)
• Google Drive backup: Export and extract the backup file

The voice notes are organized in folders by date. File names follow the pattern PTT-YYYYMMDD-WA0001.amr (older versions) or .opus (newer versions).

From Nokia/Samsung Phone Backups

Old phone backup software (Nokia PC Suite, Samsung Kies) stored recordings in proprietary backup formats. You may need:

• Nokia: Extract .nbu or .nbf backup files using NbuExplorer (free, open source)
• Samsung: Look in the backup folder for .amr files, often under Sounds/ or Voice Recorder/

From Voicemail Systems

Many voicemail systems allow you to forward messages as email attachments. The attachments are typically .amr or .wav files. If your system supports it, forward all important voicemails to your email before decommissioning the service.

Choosing the Right MP3 Settings

AMR Source	Recommended MP3 Bitrate	Sample Rate	Channels	Reasoning
AMR-NB (8 kHz)	64-96 kbps	22.05 kHz	Mono	Source has minimal frequency content
AMR-NB (archival)	128 kbps	44.1 kHz	Mono	Maximum compatibility, slight overhead
AMR-WB (16 kHz)	128 kbps	44.1 kHz	Mono	Wideband has more frequency content
For sharing	128 kbps	44.1 kHz	Mono	Universal compatibility
Minimum viable	48 kbps	22.05 kHz	Mono	Smallest file, acceptable for voice

For AMR source material, encoding to MP3 above 128 kbps provides zero benefit. The source audio simply does not contain enough frequency content to justify higher bitrates. The encoding is not adding quality — it is just preserving what the AMR file already contained in a more compatible container. For understanding how bitrate affects audio quality generally, see our audio bitrate quality guide.

Alternative Output Formats

While MP3 is the most universally compatible choice, other formats may be better for specific use cases:

• AAC (M4A): Better quality than MP3 at the same bitrate. Good choice for Apple devices. Use the AAC converter.
• OGG Vorbis: Open-source, better quality at low bitrates. Use the OGG converter.
• WAV: Uncompressed — useful if you plan to edit the audio further. Use the WAV converter.
• FLAC: Lossless container — preserves the decoded AMR audio exactly. Larger files with no quality benefit over the AMR source, but useful for archival of the decoded audio. Use the FLAC converter.

For a broader comparison of audio formats, see our AAC vs MP3 comparison and OGG vs MP3 comparison.

Frequently Asked Questions

Why can I not play AMR files on my computer?

AMR is a mobile telephony format with limited support on desktop operating systems. Windows Media Player and many music apps do not include an AMR codec. VLC media player can play AMR files (it includes its own codecs), but for long-term compatibility, converting to MP3 is the better solution.

Will converting AMR to MP3 improve the audio quality?

No. The conversion changes the container format but cannot add audio information that was not in the original recording. An AMR file recorded at 12.2 kbps with 8 kHz sample rate has a fundamental quality ceiling. However, post-processing (noise reduction, EQ, normalization) during conversion can improve the perceived clarity of the voice. The raw audio data is the same, but it can be made more listenable.

How small are AMR files compared to MP3?

Extremely small. A 1-minute AMR-NB recording at 12.2 kbps is approximately 90 KB. The same duration as a 128 kbps MP3 is approximately 960 KB — roughly 10 times larger. This extreme compression is why AMR was used for mobile voice recording when phone storage was measured in megabytes, not gigabytes.

Can I convert AMR to FLAC to preserve quality?

You can, but it is misleading. The FLAC file will be lossless — meaning it perfectly preserves the decoded AMR audio — but the decoded AMR audio is already heavily compressed and limited. The FLAC file will be much larger than the AMR file without sounding any better. MP3 at 128 kbps is a more practical choice for AMR source material.

How do I convert AMR files from WhatsApp?

WhatsApp voice notes (in AMR format) can be found in your phone's WhatsApp media folder or in a Google Drive/iCloud backup. Once you locate the .amr files, convert them using FFmpeg or our audio converter. The process is the same as any other AMR file. Newer WhatsApp voice notes use Opus format instead of AMR — these are higher quality and can be converted using the same tools.

What happened to AMR format? Why is it not used anymore?

AMR was designed for 2G/3G cellular networks where bandwidth was extremely limited. Modern phones use more efficient codecs like Opus (WhatsApp, Telegram), AAC (Apple), or codec-agnostic recording formats that leverage the dramatically increased storage and bandwidth of modern devices. AMR is still used in some cellular voice networks (VoLTE uses AMR-WB), but consumer-facing applications have moved on to better alternatives.