# Change the Speed of Audio

Listen to a lecture at 1.5×, slow a song down to learn it, or fit a voice-over into a time slot. Keep the pitch natural, or let it move with the speed like a tape.

_Source: https://sharelargefilesfree.com/tools/change-audio-speed · Updated 2026-09-29_

## How to use it

1. Choose or drop one or more audio files.
2. Pick a speed (0.25× to 4×).
3. Keep “Keep the pitch” on for natural voices, or turn it off for the tape effect.
4. Press Change speed, listen, then download or send the result.

## How the pitch is kept

With “Keep the pitch” on, the tool uses WSOLA (waveform-similarity overlap-add): it cuts the sound into overlapping 40 ms pieces, and for each piece searches ±10 ms for the spot whose waveform best continues the previous one, then lays them closer together (faster) or further apart (slower). Voices keep their natural pitch.

It works best for speech and between 0.75× and 1.5×. Dense music and extreme speeds (0.25× or 4×) can sound slightly echoey or warbly; that is a limit of the method, not a bug.

## Without keeping the pitch

Turn the option off and the audio is resampled, exactly like playing a record at the wrong speed: faster is higher (1.5× is about 7 semitones up), slower is lower. There are no time-stretch artefacts at all, which makes it the cleaner choice for effects and for slowed or sped-up music edits.

## Length and format

| Speed | A 60-minute file becomes |
| --- | --- |
| 0.75× | 80 minutes |
| 1.25× | 48 minutes |
| 1.5× | 40 minutes |
| 2× | 30 minutes |

The result is saved as MP3, M4A or WAV, processed in your browser and never uploaded. For videos, use [Change video speed](https://sharelargefilesfree.com/tools/change-video-speed).

## Frequently asked questions

### Can I speed up audio without the chipmunk effect?

Yes. Keep “Keep the pitch” on; voices stay at their natural pitch.

### What speeds are possible?

From 0.25× (four times slower) to 4× (four times faster), in steps of 0.05.

### Does it work for music?

Yes, especially between 0.8× and 1.25×. At more extreme speeds dense music can sound a little phasey with pitch kept.

### Are my files uploaded?

No. The audio is processed on your device.