Is this audio pitch 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. Pitch shifting happens entirely locally using FFmpeg compiled to WebAssembly. Your file never leaves your device.

What audio formats can I upload?

MP3, WAV, M4A, OGG, FLAC, AAC, Opus, and WebM are supported, up to 100MB per file.

How many semitones should I shift a voice?

It depends on the effect you want. A shift of 1-3 semitones is a subtle correction, often used to nudge a recording into tune. Around 3-5 semitones noticeably changes a voice's character while staying natural-sounding. Beyond about 7-8 semitones the result starts sounding processed, and a full octave (12 semitones) is a dramatic, obviously artificial transformation — useful for creative effects rather than natural-sounding results.

Why doesn't the audio speed up or slow down when I shift the pitch?

This tool uses a three-stage FFmpeg filter chain: it first reinterprets the sample rate to shift pitch (which would also change speed), then compensates with a tempo filter that restores the original duration without touching pitch again. The result is a pitch shift with no change in playback length.

Why does a big pitch shift sound robotic?

Sample-rate-based pitch shifting (the technique this tool uses) doesn't independently model the human voice or an instrument's timbre — it mathematically stretches or compresses the waveform's frequency content. At small shifts this is inaudible, but beyond roughly 7-8 semitones the formants (the resonant frequencies that give a voice its natural character) shift along with the pitch, which is what produces the telltale robotic or "helium" quality. This is an honest limitation of the technique, not a bug — professional formant-preserving pitch shifters use more complex algorithms to avoid it.