boxtool.io

Audio Converter

Convert audio files between MP3, WAV, OGG, FLAC and AAC. Runs entirely in your browser — no upload, no limits, free.

Drop an audio file or click to browse

MP3, WAV, OGG, FLAC, AAC, M4A, OPUS, WMA, AIFF

Output Format

All processing happens in your browser — your audio never leaves your device.

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Frequently Asked Questions

Input: MP3, WAV, OGG, FLAC, AAC, M4A, OPUS, WMA, AIFF and most common audio formats. Output: MP3 (192 kbps), WAV (uncompressed), OGG Vorbis, FLAC (lossless) and AAC (192 kbps). The conversion engine is FFmpeg, which supports virtually every audio format in existence.

No. Everything happens entirely in your browser using WebAssembly. Your audio file never leaves your device. There are no upload limits, no privacy concerns, and no file size restrictions beyond what your computer's memory can handle.

The first conversion downloads the FFmpeg WebAssembly engine (~25 MB) from a CDN. This only happens once — your browser caches it automatically. Subsequent conversions start immediately without any download.

Lossy formats (MP3, OGG, AAC) compress audio by discarding inaudible frequencies, reducing file size significantly at the cost of some quality. Lossless formats (WAV, FLAC) preserve the original audio data exactly. FLAC applies lossless compression, so files are smaller than WAV but still bit-perfect.

MP3 for universal compatibility (music players, streaming). WAV for professional editing or archiving (uncompressed). FLAC for high-quality archiving with smaller files than WAV. OGG for open-source projects and web use. AAC for Apple devices and modern streaming platforms.

There is no enforced limit. However, very large files (over 1–2 GB) may be slow to process since everything runs in the browser. For most audio files (up to a few hundred MB), conversion completes in seconds to minutes depending on your device.