Audio Speed Changer
Speed up or slow down any audio file while keeping pitch natural sounding. Free, no signup, works in your browser.
Everything runs inside your browser — your file is never uploaded to a server.
First run downloads the media engine (~30 MB) once, then it stays cached.
About this tool
Sometimes you need a lecture recording played faster to save time, or a music track slowed down to practice an instrument part. This tool changes audio playback speed using FFmpeg's atempo filter, which stretches or compresses time without dramatically distorting pitch the way a simple sample-rate change would. Choose any multiplier from a slight 0.5x slow-motion effect to a rapid 2x or beyond, preview the result, and export when you're satisfied. Everything runs locally through WebAssembly, so long recordings like audiobooks or full podcast episodes can be processed without waiting on a server upload or worrying about file size caps. It's a quick way to fit more listening into less time, or to slow down fast speech and music for closer study.
How to use this tool
1. Upload your audio file
Select the audio you want to speed up or slow down.
2. Choose a speed multiplier
Pick a value like 1.5x for faster or 0.75x for slower playback.
3. Process the audio
Click apply and FFmpeg adjusts the tempo locally in your browser.
4. Download the adjusted file
Save the new speed-adjusted audio to your device.
Why use this tool
Adjusting playback speed is one of the simplest ways to save time or slow down for careful listening, but most audio editors bury this feature behind a complex interface. This tool exposes it directly with a single slider, processes everything on your device for privacy, and lets you experiment freely with different speeds until the result sounds right, without any server round trips.
Tips & best practices
- Start with a moderate multiplier like 1.25x or 1.5x for spoken content; larger changes can start to sound unnatural.
- For learning a musical passage, try 0.75x or 0.5x to catch fast notes clearly.
- Combine with the volume booster if the sped-up track ends up sounding quieter than expected.
Common use cases
- Speeding up lecture or audiobook recordings to review material faster.
- Slowing down a guitar or piano solo to learn it note by note.
- Creating a faster-paced podcast version for commute listening.
- Producing a slow-motion sound effect for a video project.
- Adjusting interview audio speed to match a video's edited pacing.
Frequently asked questions
Will changing speed change the pitch of my audio?
The atempo filter is designed to preserve pitch reasonably well, though extreme speed changes can introduce some artifacts.
What speed range can I choose?
Typically from 0.5x (half speed) up to 2x or more, depending on how extreme a change you need.
Can I speed up a podcast episode for faster listening?
Yes, this is one of the most common uses, letting you listen to more content in less time.
Does this work on music as well as speech?
Yes, though very large speed changes on music can sound more noticeably altered than on speech.
Is my audio file uploaded anywhere?
No, the entire speed change happens locally in your browser.
Share this tool
Was this tool helpful?
97% · 168 people found this tool helpful