FileopiaChange Audio Speed & Pitch
Speed up or slow down MP3, WAV, M4A and other audio files without changing pitch, or shift the pitch by semitones. Save as MP3 or WAV. Free, private, in your browser.
- Upload
- Options
- Download
- ✓ 100% free
- ✓ No sign-up
- ✓ No limits
- 🔒 Files never leave your device
How to: Change Audio Speed & Pitch
- Upload an audio or video file.
- Set speed, pitch and whether to keep the original pitch.
- Download the processed MP3 or WAV.
Lectures and podcasts are often easier to digest at 1.25× or 1.5×, a difficult guitar solo is easier to learn at 0.7×, and a backing track might need to be a semitone lower for your voice. This tool changes speed and pitch independently. Keep the pitch while changing tempo, shift the pitch while keeping the length, or change both together like a tape machine.
Common uses
- Speed up lectures, audiobooks and voice notes to save time.
- Slow down songs to learn instruments, dances or lyrics.
- Transpose backing tracks to suit a singer's range.
- Create chipmunk, slow-motion or nightcore-style effects.
Tips for best results
- 1.25×–1.5× keeps speech clear for most listeners.
- Use WAV output if you will edit the audio further.
- Untick “Keep original pitch” for a classic vinyl or tape-speed effect.
- Large pitch shifts sound more natural on speech than on complex music.
Time-stretching explained
Changing speed without changing pitch uses an algorithm called WSOLA (waveform-similarity overlap-add). It cuts the sound into short overlapping pieces, then lays them closer together or further apart, choosing the best alignment for each piece so the waveform stays continuous. Pitch shifting combines time-stretching with resampling.
Private processing
The audio is decoded and processed in your browser. Nothing is uploaded, which also makes it quick for long recordings.
Why use Fileopia for Change Audio Speed & Pitch?
| Fileopia | Typical upload-based sites | |
|---|---|---|
| Files uploaded to a server | No – processed on your device | Yes |
| Sign-up required | Never | Often for bigger jobs |
| Hourly / daily task limits | None | Common on free plans |
| Watermark on output | Never | Sometimes |
| Works offline after loading | Yes, for most tools | No |
Your files never leave your device
Change Audio Speed & Pitch runs entirely in your browser using JavaScript and WebAssembly. Your files are read from your disk into this tab, processed in memory and saved straight back to your downloads folder – they are never uploaded to Fileopia or any third party.
- Test it yourself: once this page has loaded, switch off Wi‑Fi or mobile data and run the tool – it keeps working.
- Check the network: open your browser’s developer tools (F12 → Network) while processing; you will see no file upload requests.
- Nothing to delete: close the tab and the data is gone – there is no server copy, no retention period and no account.
Frequently asked questions
Can I slow down music without changing the key
Yes. With “Keep original pitch” ticked the tool uses time-stretching, so a song at 0.75× plays slower but stays in the same key – handy for learning an instrument.
Can I change pitch but keep the length
Set speed to 1 and choose a pitch shift in semitones. Twelve semitones equals one octave; one or two semitones is useful for transposing songs to a singer's range.
Is Change Audio Speed & Pitch really free?
Yes. Every tool on Fileopia is 100% free with no file limits, no sign-up and no watermarks. The site is supported by unobtrusive ads.
Are my files uploaded to a server?
No. Fileopia processes your files directly in your browser using JavaScript. Your documents never leave your device, so they stay completely private.
Does it work on mobile?
Yes. Fileopia works in any modern browser on Android, iPhone, iPad, Windows, Mac and Linux.