Music Speed Changer: Slow Down or Speed Up Any Song
Drop a song and this music speed changer makes it slower or faster — from 0.25× to 3× — while keeping the original key, or letting the pitch move with the speed like a turntable. Add reverb for a slowed + reverb edit, preview instantly and download WAV or MP3. The music speed changer runs entirely in your browser, so your audio never leaves your device. Free, no sign-up — made by MusicGenerator.so.
Drop a song here to change its speed
MP3, WAV, FLAC, M4A, AAC, OGG, OPUS · up to 20 min · up to 200 MB
100% in your browser: the music speed changer decodes, processes and encodes your file on your device. Nothing is uploaded.
How to use the music speed changer
- 1
Drop your song
Choose an MP3, WAV, FLAC, M4A or OGG file, or drag it onto the music speed changer. The file is opened only inside your browser.
- 2
Set the speed
Move the slider or pick a preset. Leave “Keep original pitch” on to change only the tempo, or switch it off for a vinyl-style effect. Press Preview to listen instantly.
- 3
Render and download
Add reverb or a semitone shift if you like, choose WAV or MP3 and press Render. The music speed changer builds the new file on your device.
Why use this music speed changer
Speed and pitch, separately or together
Most players can only play faster or slower. This music speed changer gives you both options: time-stretching, which changes the tempo but keeps every note in the same key, and resampling, which changes speed and pitch together exactly like speeding up a record.
Private by design
Many online tools upload your song to a server. This music speed changer does not: decoding uses the Web Audio API, the time-stretch runs in a Web Worker and the MP3 encoder runs in another worker, all on your device.
Made for practice and for edits
Slow a guitar solo to 0.75× to learn it in the original key, speed up a lecture to 1.5×, or make a slowed + reverb or nightcore edit in seconds. The music speed changer shows the new length and pitch before you render.
Free and unlimited
No account, no credits and no watermark. Use the music speed changer on as many files as you like, up to 20 minutes each.
Who it’s for
Musicians
Use the music speed changer to slow down a fast passage without changing its key, practise along at 70–90 % and raise the speed as you improve.
Singers
Use the music speed changer to shift a backing track a few semitones to fit your voice while keeping the same tempo.
Creators & editors
Use the music speed changer to make slowed + reverb or sped-up versions, or fit a song to the length of a video.
Students & listeners
Speed up lectures, audiobooks and podcasts, or slow down language lessons.
How the music speed changer works
Changing speed sounds simple, but keeping the pitch while doing it needs a time-stretch algorithm. Here is what happens to your file.
1. Decode
Your browser decodes the file to raw samples at its original sample rate, in stereo when the source is stereo.
2a. Keep pitch: WSOLA time-stretch
With pitch lock on, the music speed changer cuts the audio into overlapping 46 ms windows and places them closer together or further apart. Before each window is added, it searches for the position that best matches the previous one (waveform-similarity overlap-add, WSOLA), which avoids phasing and clicks.
2b. Vinyl style: resample
With pitch lock off, the samples are simply played back faster or slower with cubic interpolation, so 1.25× sounds about 3.9 semitones higher and 0.8× about 3.9 semitones lower.
3. Pitch and reverb
A semitone shift resamples the audio and then time-stretches it back to the chosen length. Reverb is added with a convolution reverb in an offline Web Audio graph.
4. Export
The music speed changer writes a 16-bit WAV directly, or encodes a 192 kbps MP3 with the open-source LAME encoder, loaded only when you choose MP3.
Music speed changer features
0.25× to 3× speed
Fine control in 0.01 steps plus one-click buttons for 0.5×, 0.75×, 1.25×, 1.5× and 2×.
Runs on your device
The music speed changer never uploads your audio. Close the tab and it is gone.
Keep or change the key
Pitch lock on for practice, off for a turntable effect, or ±12 semitones on top for transposing.
Slowed + reverb
One preset gives you the slowed + reverb sound; the reverb slider goes from dry to washed-out.
WAV or MP3 export
Lossless 16-bit WAV for editing, or 192 kbps MP3 for sharing.
Instant preview
Hear the new speed right away before you render, and see the new length before you export.
Tips for natural-sounding results
- Between about 0.75× and 1.5× the music speed changer is hard to tell from the original. Past 2× or below 0.5× any time-stretch starts to sound metallic or smeared.
- Learning a solo? Start at 0.7×–0.8× with pitch lock on, then raise the speed by 5 % each time you can play it cleanly.
- For a slowed + reverb edit, turn pitch lock off and use 0.8×–0.9× with 30–50 % reverb. The lower pitch is part of the sound.
- For nightcore or sped-up edits, turn pitch lock off and use 1.2×–1.3×.
- Need to know the new tempo? The new BPM is the old BPM × speed: a 100 BPM song at 1.2× becomes 120 BPM. Find the original with our BPM Detector.
- Export WAV if you will edit the result further, and MP3 when you only want to listen or share.
Common speeds and what they do
What each setting in the music speed changer does to tempo, length and pitch (with pitch lock off the pitch moves; with it on the key stays).
| Music speed changer setting | Tempo / length | Pitch with lock off |
|---|---|---|
| 0.5× | Half tempo, twice as long | −12 semitones (one octave down) |
| 0.75× | −25 % tempo, 1.33× longer | ≈ −5 semitones |
| 0.85× | Typical slowed edit | ≈ −2.8 semitones |
| 1.25× | +25 % tempo, 0.8× length | ≈ +3.9 semitones |
| 1.5× | Podcast / lecture speed | ≈ +7 semitones |
| 2× | Double tempo, half length | +12 semitones (one octave up) |
Go beyond the music speed changer with MusicGenerator.so
Changing the speed of an existing song is one thing — making a new one at exactly the tempo you want is another. MusicGenerator.so is an AI music generator that turns a text prompt or your own lyrics into a full song with vocals or an instrumental, in any genre and at any BPM.
- Full songs with vocals from one prompt
- Instrumentals in any genre and tempo
- Vocal Remover and BPM Detector included
- Commercial license on paid plans
Only process audio you have the right to use. Extreme speed changes can add audible artefacts with any time-stretch algorithm.
Frequently asked questions
More free AI music tools
Changed the speed? Now make your own song
Use the music speed changer for practice and edits, then let MusicGenerator.so — the AI music generator — create a brand-new track at the tempo you want.
Last updated October 2026.