Online Audio Speed Changer — Speed Up or Slow Down Audio

What is the Online Audio Speed Changer?

The Online Audio Speed Changer lets you adjust how fast or slow an audio file plays back. You can slow a lecture down to 0.5x to take better notes, or crank a podcast up to 2x to get through it in half the time — all without changing the speaker’s pitch, so voices and instruments still sound natural.

The tool runs entirely in your browser using FFmpeg.wasm. Your files stay on your device throughout the process.

How to Change Audio Speed

1. Upload your file — select the audio file you want to modify.
2. Adjust the speed — drag the slider to your desired multiplier (0.25x to 4.0x).
3. Toggle pitch (optional) — check the box if you want the pitch to shift naturally with the speed instead of staying fixed.
4. Apply — click the button to process the audio.
5. Preview and download — listen to the result, then save it to your device.

Use Cases

Music practice — slow down a difficult guitar solo, piano run, or drum fill to 50% speed so you can isolate each note. This is one of the most popular uses among musicians learning by ear.

Language learning — reduce the speed of a native-speaker audio clip to 70–80% to clearly hear pronunciation and pick apart fast-spoken phrases.

Podcast and lecture efficiency — play back audio content at 1.5x or 2x to consume more material in less time. The pitch-preservation algorithm keeps voices intelligible even at high speeds.

Content repurposing — speed up or slow down a clip to fit a specific duration requirement for a video edit or presentation.

Why Use This Tool

Desktop audio editors like Audacity can handle speed changes, but they require installation and a learning curve. Online tools that promise the same result often upload your file to a remote server. This tool does neither — it processes your audio locally, instantly, and privately using modern browser technology.