Change audio speed
Speed a recording up or slow it down without turning voices into chipmunks.
- Runs on your device — the file is never sent anywhere
- No sign-up, no watermarks, no daily quotas
- Free, with no limit on how often you use it
How it works
Speeding up audio is how most people get through lectures, podcasts and recorded meetings. Slowing it down is how you transcribe a mumbled interview or learn a piece of music by ear. Both need the pitch to stay put, or the result is unlistenable.
Pitch is preserved
Naively playing audio faster raises its pitch, which is why fast-forwarded speech sounds absurd. This uses time-stretching, which changes the duration while leaving the pitch where it was. Voices stay recognisably themselves.
How far you can push it
Up to about 2× speech remains completely natural. Beyond that it stays intelligible but starts to sound processed, and at 3× consonants begin to smear. Slowing down is more forgiving: half speed sounds clear, which is why it suits transcription.
Length changes accordingly
At 1.5× a sixty-minute recording becomes forty minutes; at 2× it becomes thirty. That arithmetic is the entire appeal.
What you get back
An MP3 at 192 kbps. The original is untouched.
Change audio speed — questions
Will voices sound higher or lower?
No. The pitch is preserved, so only the speed changes.
How fast can I go before it sounds bad?
Up to 2× is comfortable for speech. Beyond 3× consonants begin to smear.
Does it work for music?
Yes, though time-stretching music is more audible than time-stretching speech, especially at extremes.
Is my file uploaded?
No. Everything runs in your browser.