Is this audio volume changer really free?

Yes. There's no signup, no watermark, and no limit on how many files you process — everything runs in your browser.

Does my audio get uploaded to a server?

No. Volume changes are computed locally with the Web Audio API. Your file never leaves your device unless you choose to export as MP3, which also runs locally via FFmpeg compiled to WebAssembly.

What's the difference between boosting and normalizing?

Manual gain applies the exact dB change you choose, which can clip if you push it too far. Normalize instead looks at the loudest point in your file and calculates the precise gain needed to bring it to a safe target level (like -1 dBFS) without exceeding it — it's the safer choice when you just want consistent volume.

Why does my audio sound distorted after boosting?

That's clipping. Digital audio can't represent a sound louder than 0 dBFS — when a boosted sample would exceed that ceiling, it gets flattened off instead, which produces a harsh, crackling distortion. We scan your result and tell you exactly what percentage of samples clipped so you're never guessing. If you hear distortion, lower the gain or use Normalize instead, which is designed to avoid clipping by construction.

What audio formats can I upload and download?

You can upload MP3, WAV, M4A, OGG, FLAC, AAC, Opus, or WebM. The processed result can be downloaded as lossless WAV or re-encoded as MP3 at your chosen bitrate.

What peak level should I normalize to?

-1 dBFS is a safe default that leaves a small safety margin. Use -0.1 dBFS if you want it as loud as possible without clipping, or -3 to -6 dBFS if the file will be processed further downstream and you want extra headroom.