Speed up or slow down an audio file
Change an audio file's playback speed from 0.5x to 2x, entirely in your browser.
Read locally, nothing is uploaded.
Anywhere from half speed to double speed, previewed as a new duration.
A re-timed WAV file, processed entirely in your browser.
Frequently asked
Is my audio uploaded anywhere?
No. It's decoded, processed, and re-encoded entirely in your browser.
Does the pitch change too?
Only if you leave "Preserve pitch" off - by default this changes speed by resampling, so pitch moves with it (a slowed-down voice sounds lower, a sped-up one sounds higher). Turn "Preserve pitch" on to keep the original pitch at any speed, using a real time-stretch algorithm (WSOLA) instead of a plain resample.
What does the Pitch shift slider do?
It changes pitch independently of speed - shift up or down by semitones without changing how long the clip is, the opposite tradeoff of the speed slider. You can combine both: change speed and preserve pitch, then shift that pitch somewhere else on top.
Why does "Preserve pitch" take longer?
A plain speed change is a cheap resample. Preserving pitch runs a real time-stretch algorithm (WSOLA) that searches for the best-aligned waveform match every few milliseconds of audio, which is meaningfully more CPU work - worth it for how much more natural the result sounds, but not instant on longer clips.
What speed range is supported?
0.5x (half speed) up to 2x (double speed), plus up to an octave of pitch shift in either direction.