Change audio speed

When you change audio speed, the pitch can change with it or stay the same, and here you choose. Pick a file, set the tempo (50 to 200%) or shift the pitch in semitones and save as MP3 or WAV. Everything runs in your browser; the file is not uploaded.

Source: Verhelst, W., Roelands, M. (1993): An overlap-add technique based on waveform similarity (WSOLA) for high quality time-scale modification of speech, IEEE ICASSP. Updated: 2 October 2026.

How it is calculated

In short: play a recording faster and you hear it higher, like a record at the wrong speed. This tool can separate the two: in the “Change tempo, keep pitch” mode the recording is stretched or squeezed without voices sounding higher or lower.

How it works

Drop or choose an audio file or video.
Pick the mode: tempo, pitch, or both like a record.
Set the sliders. The new length is shown below.
Choose a format (MP3 or WAV) and click “Convert and save audio”. You can listen to the result right away.

The modes

Change tempo, keep pitch: the method is called WSOLA and splices small segments so that the waveform continues seamlessly. Good for speech, podcasts, audiobooks and lectures.
Change pitch, keep tempo: shifts up or down by up to 12 semitones (one octave), for example to suit your own voice.
Record effect: tempo and pitch change together. Faster means higher, slower means lower, as with a record or tape.

Honest limits

With strong stretching or squeezing (below 70% or above 150%) and with dense music, slight sound artefacts can become audible. Speech copes better than music.
When you raise the volume, peaks above 0 dB are hard-limited, so a strong boost can distort.
30 minutes per file are possible; stereo is processed as two channels and further channels are dropped.

Privacy

The file is processed only in your browser and is not uploaded.

Frequently asked questions

How can I change the speed of an audio file?

Choose the file, keep the “Change tempo, keep pitch” mode, set the slider to for example 125% and click “Convert and save audio”.

How do I speed up a recording without the voice sounding higher?

That is exactly what the “Change tempo, keep pitch” mode is for. It stretches or squeezes the recording with the WSOLA method and leaves the pitch unchanged.

Can I change only the pitch?

Yes, in the “Change pitch, keep tempo” mode. You shift the pitch by up to 12 semitones and the length of the file stays the same.

Which speeds are possible?

From 50% (half speed) to 200% (double speed). For speech, 80 to 150% usually sounds natural.

Is my file uploaded?

No. The conversion runs entirely in your browser; the file never leaves your device.

Which formats can I save?

MP3 (128 to 320 kbit/s) and WAV. Common audio formats and the sound of videos work as a source.

Sources and legal basis

As of: 2 October 2026 · Editorial policy