Change Audio Speed Online — Free, With Pitch Correction
Speed up or slow down any audio file without changing the pitch. Uses WSOLA time-stretching for natural-sounding results. No upload required.
Drop audio file here or click to browse
MP3, WAV, OGG, FLAC, and more
Disable for classic chipmunk / slow-motion effects
How Audio Speed Changing Works
Changing audio speed without affecting pitch requires a time-stretching algorithm. This tool uses WSOLA (Waveform Similarity Overlap-Add), a well-established algorithm that rearranges overlapping waveform segments to compress or expand the audio timeline while maintaining tonal quality.
With pitch correction enabled, the audio plays faster or slower while voices and instruments retain their natural pitch. This is how podcast apps implement 1.5× or 2× playback, and how musicians slow down recordings to learn complex passages.
With pitch correction disabled, speed changes affect pitch directly — speeding up raises the pitch, slowing down lowers it. This is the classic tape-speed effect, useful for creative or comedic purposes.
Popular Use Cases
- Speed up podcasts and lectures to 1.5× or 2× for faster listening
- Slow down music to 0.5× or 0.75× to learn a guitar solo or transcribe notes
- Extend a short background music loop to fill a longer video
- Adjust the timing of a voice-over to match a video clip duration
- Create slow-motion audio effects for soundscapes
- Practice language learning by slowing down native speech
Frequently Asked Questions
What is pitch correction and why does it matter?
Without pitch correction, doubling the speed also doubles the pitch (chipmunk effect). The WSOLA algorithm time-stretches the audio independently of pitch so that a 2× speed recording sounds like a fast but natural version of the original.
What speed range is available?
You can set any speed from 0.25× (quarter speed) to 4× (four times speed). The best quality results are in the 0.5× to 2× range. Extreme values may introduce some audio artifacts.
How long does processing take?
Short files (under 10 minutes) typically process in a few seconds. Longer files may take 20–60 seconds depending on your device speed. WSOLA is compute-intensive but runs entirely in your browser.
Are my files uploaded to a server?
No. All processing happens locally in your browser. Your audio files never leave your device.