Your audio stays on your device
When you choose an audio file, Music Tools Lab opens and processes it in your browser. BPM and key analysis, waveform display, audio conversion, trimming, MP3 export and vocal reduction all happen on the device you are using. The selected file is not uploaded to a Music Tools Lab server.
Because the work happens locally, you should keep the tab open until an analysis or export is complete. Processing speed depends on the length of the file and the memory available on your phone or computer.
Understanding automatic results
Duration, channel count and audio levels are measurements from the file your browser opened. BPM and musical key are estimates based on patterns in the recording. Energy, brightness, stereo width and broad style suggestions are most useful for comparing music inside the same tool.
A clear result means the recording contains a stronger, more consistent pattern. It does not guarantee that every listener, DJ grid or piece of music theory will use the same interpretation.
When to double-check
Live performances, quiet recordings, spoken audio, unusual time signatures, tempo changes and music without a clear tonal center can produce uncertain or unexpected answers. Try a representative section, compare half-time and double-time values, or check the result with Tap Tempo, a metronome or an instrument.
Genre suggestions are broad and can overlap. Vocal reduction works best when the lead vocal is centered in a stereo mix; reverb, backing vocals and centered instruments may remain or become quieter too.
Playlist search and privacy
Playlist generators can search a public music catalog for the artist, genre, mood or song words you enter. Only that search text is sent to the catalog service. Music Tools Lab does not send your uploaded audio or an imported CSV or M3U library with the request.
Catalog results provide real titles, artists and durations, but they do not include verified BPM or energy data. Tempo ranges are therefore shown as playlist guidance unless your own imported file contains those values.
Supported files and practical limits
Most tools accept common browser-supported audio such as MP3, WAV, M4A and FLAC. Actual support can vary by browser and device. Audio files are limited to 50 MB and twenty minutes so local processing remains manageable. BPM Changer also estimates its full decoded and export working set, so long high-rate stereo files can be rejected earlier.
WAV export is uncompressed and creates a larger file. MP3 export creates a smaller file by encoding the selected audio again. Very long files can take longer to process, especially on a phone, and may need a desktop browser.
Clear guidance for every tool
Each tool page explains what the result means, how to improve it and which limitations matter for that specific job. Technical references are included as optional further reading, while the main instructions stay practical and easy to follow.
If an answer does not match what you hear, trust the listening check. Music Tools Lab is designed to make the next step faster, not to replace musical judgment.