Convert Any Audio or Video to MP3

MP3 is a lossy audio compression format that achieves small file sizes by removing audio frequencies the human ear struggles to perceive — a technique called perceptual coding. A 4-minute song that might be 40 MB as uncompressed WAV can shrink to just 4–8 MB as MP3 with minimal audible difference at 192 kbps or higher.

The trade-off is irreversibility: once audio is encoded as MP3, the removed frequencies cannot be recovered. This is why audio professionals work in lossless formats (WAV, FLAC) and only convert to MP3 for the final distribution copy.

Bitrate determines how much data is used per second of audio — higher bitrate means higher quality and larger file size:

At 320 kbps, most listeners — even in double-blind tests with high-end headphones — cannot distinguish MP3 from the lossless source.

• MP3 — Maximum compatibility. Use for sharing, streaming, and any case where wide device support matters.
• AAC — Better compression than MP3 at the same bitrate. Preferred by Apple devices and YouTube. Use if you're in the Apple ecosystem.
• FLAC — Lossless, larger files. Use for archiving your music library or when you need bit-perfect audio for mastering.
• WAV — Uncompressed lossless. Use for professional audio production, DAW projects, and any workflow requiring editing without re-encoding artefacts.
• OGG Vorbis — Open-source, excellent compression. Preferred for games, web apps, and open-source projects.

Extracting audio from video is one of the most common use cases for an MP3 converter. Common scenarios include:

• Extracting the soundtrack from a lecture recording (MP4) for audio-only review
• Pulling a song from a concert video for your music library
• Saving a podcast that was published as video-only

TransmuteBox handles this automatically — when you upload an MP4, MKV, MOV, or AVI file, FFmpeg demuxes the audio stream and re-encodes it as MP3 at your chosen bitrate. The video data is discarded entirely, resulting in a clean audio-only MP3 file.

Poor quality output despite high bitrate: This happens when the source audio is already low quality. You cannot gain quality that wasn't in the original — always use the highest quality source available.

Missing ID3 tags after conversion: Some converters strip metadata. TransmuteBox preserves ID3 tags (artist, title, album) by default when converting from formats that carry them.

Volume is too low or too loud: Our converter does not apply any volume normalisation by default. If you need loudness normalisation, use our Audio Compressor with dynamic range settings.