GSM to MP3 Converter

Convert GSM audio files to MP3 format

Click to upload file or drag and drop file here

Maximum file size: 20MB Supported formats: audio/gsm, audio/x-gsm, .gsm, .gsm-t

Upload a GSM file to convert to MP3

GSM is 13 kbps. 128 kbps recommended for voice audio.

Key Facts

Category
Images, Audio & Video
Input Types
file, select, checkbox
Output Type
file
Sample Coverage
4
API Ready
Yes

Overview

The GSM to MP3 Converter allows you to easily transcode legacy GSM audio files, commonly used in telephony and voicemail systems, into the widely compatible MP3 format. By uploading your .gsm or .gsm-t files, you can customize output settings such as bitrate, sample rate, and audio channels to ensure optimal playback quality on modern media players and devices.

When to Use

  • •When you need to play legacy voicemail recordings or call center logs on modern smartphones, tablets, or computers.
  • •When preparing telephony audio files for transcription software that does not natively support the GSM format.
  • •When archiving old voice recordings in a highly compatible, compressed format like MP3 to save space while maintaining audio clarity.

How It Works

  • •Upload your GSM audio file (.gsm or .gsm-t) using the file selector.
  • •Configure your output preferences, including the target bitrate, sample rate, and audio channels (mono or stereo).
  • •Choose whether to preserve existing metadata tags during the conversion process.
  • •Click the convert button to process the file and download your high-quality MP3 audio.

Use Cases

Converting archived call center voice recordings to MP3 for quality assurance reviews.
Exporting legacy PBX voicemail messages to a playable format for legal or administrative documentation.
Preparing historical telephony voice samples for integration into modern digital archives or presentations.

Examples

1. Converting Legacy Voicemails for Legal Review

Legal Assistant
Background
A legal assistant needs to present old voicemail evidence stored on a legacy PBX system in court, but the playback software only supports MP3.
Problem
The original files are in .gsm format and cannot be played on standard courtroom laptops.
How to Use
Upload the .gsm voicemail file, set the bitrate to 128 kbps, select Mono channels, and keep metadata enabled.
Example Config
Bitrate: 128 kbps, Sample Rate: Auto, Channels: 1 (Mono), Keep Metadata: True
Outcome
A highly compatible MP3 file that plays perfectly on any standard media player while preserving the original voice clarity.

2. Archiving Call Center Recordings

IT Administrator
Background
An IT administrator is migrating historical call logs from an old telephony server to a modern cloud storage system.
Problem
The legacy .gsm-t files need to be converted to a standard format to ensure long-term accessibility and compatibility with modern transcription tools.
How to Use
Upload the .gsm-t file, select a sample rate of 16 kHz for enhanced voice quality, and set the bitrate to 96 kbps to optimize storage space.
Example Config
Bitrate: 96 kbps, Sample Rate: 16000 Hz, Channels: 1 (Mono), Keep Metadata: True
Outcome
Compressed MP3 files that occupy minimal storage space while remaining fully compatible with modern speech-to-text transcription APIs.

Try with Samples

audio, file
GSM Audio Sample
GSM encoded audio sample for telephony playback, upload, and format conversion workflows
title token gsm
audio
Copyright-Free MP3 Audio Samples
Collection of royalty-free audio samples for testing and development purposes including nature sounds, meditation music, and ambient audio
title token mp3
audio
AMR Narrowband Audio Sample
AMR-NB voice audio sample for telephony playback, upload, and format conversion workflows
preferred input family audio
audio
Copyright-Free FLAC Audio Samples
Lossless FLAC audio samples for testing and development, mirrored from MP3 set with nature sounds and meditation music
preferred input family audio
audio

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FAQ

What is a GSM file?

A GSM file is an audio format designed for telephony use, optimized for recording human speech like voicemails and call logs.

What bitrate should I choose for voice recordings?

A bitrate of 128 kbps is recommended for voice audio to balance file size and sound quality, though GSM itself is natively 13 kbps.

Can I convert multiple channels?

Yes, you can choose to output as Mono (recommended for voice) or Stereo, or keep the original channel configuration.

Will I lose the metadata tags from my original file?

No, if you keep the 'Keep Metadata' option checked, the converter will preserve title and artist tags when available.

What is the maximum file size supported?

The converter supports GSM audio files up to 20 MB in size.

API Documentation

Request Endpoint

POST /en/api/tools/gsm-to-mp3

Request Parameters

Parameter Name Type Required Description
audioFile file (Upload required) Yes Upload a GSM file to convert to MP3
bitrate select No GSM is 13 kbps. 128 kbps recommended for voice audio.
sampleRate select No -
channels select No -
keepMetadata checkbox No -

File type parameters need to be uploaded first via POST /upload/gsm-to-mp3 to get filePath, then pass filePath to the corresponding file field.

Response Format

{
  "filePath": "/public/processing/randomid.ext",
  "fileName": "output.ext",
  "contentType": "application/octet-stream",
  "size": 1024,
  "metadata": {
    "key": "value"
  },
  "error": "Error message (optional)",
  "message": "Notification message (optional)"
}
File: File

AI MCP Documentation

Add this tool to your MCP server configuration: 

{
  "mcpServers": {
    "elysiatools-gsm-to-mp3": {
      "name": "gsm-to-mp3",
      "description": "Convert GSM audio files to MP3 format",
      "baseUrl": "https://elysiatools.com/mcp/sse?toolId=gsm-to-mp3",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

You can chain multiple tools, e.g.: `https://elysiatools.com/mcp/sse?toolId=png-to-webp,jpg-to-webp,gif-to-webp`, max 20 tools.

Supports URL file links or Base64 encoding for file parameters.

If you encounter any issues, please contact us at [email protected]