Convert Audio Between Formats
This free audio converter runs entirely in your browser using the WebCodecs API. Convert M4A and MP4 audio files to AAC (M4A) for efficient compressed audio, or to WAV for uncompressed lossless quality — without uploading your files to any server.
Output Format Comparison
| Format | Type | Size (per min) | Best For |
|---|---|---|---|
| AAC (M4A) | Lossy | ~1-2 MB | Music, streaming, Apple devices, general use |
| WAV | Uncompressed | ~10 MB | Audio editing, recording, mastering, archival |
Understanding Lossy vs Lossless
AAC is a lossy format that discards audio information most listeners can't hear, achieving 5-10x compression. It offers better quality than MP3 at the same bitrate and is the standard for Apple Music, YouTube, and most streaming services. WAV is uncompressed and preserves every sample of the original recording — ideal for editing or archival.
Technical Details
This tool uses your browser's built-in WebCodecs API for hardware-accelerated audio encoding and decoding. No external libraries are downloaded — the codecs are already part of your browser. This means faster processing, smaller page loads, and maximum privacy.
All processing is local. Your audio files never leave your device.