Nouplo

Change audio speed

Faster or slower sound, at the same pitch.

Drop files here

or click to choose from your deviceAccepted: MP3, M4A, AAC, WAV, OGG, OGA, OPUS, FLAC, WEBA

Up to 3 files per runUp to 20 MB per file10 runs per dayRemove limits with Pro✓ Works offline

Your files stay on your device

This tool runs entirely in your browser. Nothing is uploaded, nothing is stored, and you can even turn off your internet connection before you start.

How it works

  1. Drop one or more audio files onto the box: MP3, M4A, WAV, OGG, FLAC and others.
  2. Choose the speed: above 1 is faster and shorter, below 1 slower and longer.
  3. Keep the pitch for speech and for practising music; choose to change it for a sped-up or slowed-down effect.
  4. Select Change speed and download the result.

Frequently asked questions

Does the voice sound higher when it is faster?
Not unless you want it to. Keep pitch stretches the sound in time only (WSOLA, which pieces together short overlapping slices of the recording at the new pace), so voices keep their pitch and stay understandable. Change pitch plays it like a tape at another speed: faster and higher, or slower and lower.
How fast can speech go and still be followed?
Most people follow speech comfortably at 1.5× and with effort at 2×. Beyond that the slices the stretching is made of start to be heard. For music practice, 0.75× keeps the notes and the key while giving the fingers time.
Does it take long?
A song takes seconds. An hour-long recording takes a minute or two on an ordinary computer, most of it spent writing the MP3; saving as M4A or WAV is quicker.
Is my file uploaded, and what are the free limits?
Nothing is uploaded. The free plan allows 3 files of up to 150 MB per run and 10 runs a day. Pro removes these limits.

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