Free is enough for most one-off jobs. Pro raises the file and batch caps; Pro + Media unlocks GB-scale streaming and unlimited duration.
Larger files supported on Developer (5 GB CSV) and Enterprise (unlimited). All processing happens in your browser — files never reach a server.
Drop your audio file
Set tempo as a percentage (50%-200%)
Download the tempo-adjusted file
0 bytes uploaded. Tempo Changer runs entirely in your browser using FFmpeg.wasm 8.1, RNNoise, and the Web Audio API. Your audio stays on your device at all times. No data is sent to any server — critical for sensitive interviews and confidential calls.
They're the same operation under the hood. Tempo is expressed as a percentage (musicians' convention), time-stretch as a factor.
Stretch or compress audio duration (0.5x-2x) while preserving original pitch. Perfect for matching video edits.
Open toolChange audio pitch by semitones or cents while keeping the original duration intact. FFmpeg rubberband-style processing.
Open toolDetect the tempo of any song using local energy-based onset detection and autocorrelation. Pure browser CPU, no upload, no account.
Open tool