Audio Speed Changer
Speed up or slow down audio without changing its pitch
Your files are processed on your device. The first use downloads a processing engine, which your browser then keeps.
Drop an audio fileTap to choose an audio file
or click to browseor tap to choose
Change playback speed without altering pitch
Large files (over 500 MB) may take longer or run out of browser memory
About Audio Speed Changer
Speeds up or slows down an audio file without changing its pitch — unlike simply playing a file faster (which raises pitch, the "chipmunk" effect), this keeps voices and music sounding natural at a different speed. Runs entirely in your browser — the audio never leaves your device.
Upload your audio file, choose a speed (0.5x to 4x) and click Change Speed. You can listen to the result right on the page, with its exact length, before downloading; the trial use is only taken when you download. Pitch stays the same unless you also move the Pitch slider (up to an octave either way), which is separate from speed.
This works well up to about 2x or down to about 0.5x — pushed further than that, audio can start to sound artifacted or robotic since the underlying technique has to stretch or compress the waveform more aggressively while trying to preserve pitch.
Watch: Audio Speed Changer in Action
- Will speeding up my audio make it sound like a chipmunk?
- No — unlike simply playing a file faster (which raises pitch, the classic "chipmunk" effect), this keeps voices and music sounding natural at a different speed by adjusting speed and pitch independently.
- How extreme a speed change can this handle?
- It works well up to about 2x or down to about 0.5x. Pushed further than that, audio can start to sound artifacted or robotic, since the technique has to stretch or compress the waveform more aggressively while trying to preserve pitch.
- Will the voice sound higher when I speed it up?
- No. The tool changes the tempo while holding the pitch, so a 1.5x file still has the same voice tone, only faster. If you hear a slight warble, it comes from the stretching method, not a pitch change.
- What speeds can I pick?
- Anything from 0.5x to 4x in steps of 0.05 using the slider, plus preset buttons for 0.5x, 0.75x, 1x, 1.25x, 1.5x, 2x, 2.5x, 3x and 4x. The label also shows how long the new file will be.
- Can I change the pitch as well as the speed?
- Yes. A separate Pitch slider moves the pitch up or down by as much as an octave (12 semitones), independently of the speed slider. Leave it in the middle and the pitch stays exactly as it was. The result keeps your file's own sample rate.
- Can I hear the result before I download it?
- Yes. After you press Change Speed the processed audio appears on the page with its exact length, and you can play it there. Playing it costs nothing; a trial use is only taken when you download.
- Why is Change Speed disabled?
- It is disabled while the speed sits at 1x and the pitch is unchanged, since that would produce an identical file. Move a slider or choose a preset. It is also disabled during processing and if the file exceeds the size limit that a notice would show.
- Does it work on a video file?
- The upload accepts audio, but the processing maps only the first audio stream and drops any picture, so a video that your browser lets through would come out as audio only. Use a video tool if you need picture and sound to stay together.
- What is the output format and name?
- The format follows the source family: WAV stays WAV, FLAC stays FLAC, M4A-type files stay M4A, OGG-type files stay OGG and everything else becomes MP3. The name is speed_ plus the multiplier and the original name.
How to use Audio Speed Changer
Drop an audio file and move the Speed slider, which spans 0.5x to 4x in steps of 0.05. The label above it shows the new length next to the old one, for example a clip going from 10:00 to 5:00 at 2x. Presets beneath the slider jump straight to 0.5x, 0.75x, 1x, 1.25x, 1.5x, 2x, 2.5x, 3x or 4x. A Pitch slider below it is optional and independent of speed.
Press Change Speed, which stays disabled at exactly 1x with the pitch unchanged. When processing ends, play the result in the preview, which also shows its exact length, and use the download button; the file name begins with speed_ and the chosen number, such as speed_1.5x_. The pitch is held steady, so voices do not turn into chipmunks.
When to use it
Speeding up a long lecture or voice memo so you can review it faster, slowing a fast speaker to transcribe a conversation, practicing a language with slowed audio, or slowing a song passage to work out a melody. It also helps when a narration is a few seconds too long and you need a small tweak such as 1.05x.
When not to use it
By default the pitch is kept constant; the separate Pitch slider shifts it by up to an octave either way, independently of speed. For repairing timing inside part of a recording, use an editor. And if you need the music to stay perfectly clean at 3x or 4x, expect artefacts, since extreme stretches cannot be hidden.
Tips for best results
Spoken word usually stays clear up to about 2x and down to 0.5x; beyond that you may hear a warbling or robotic tone. Because the slider moves in 0.05 steps, tiny corrections like 0.95x or 1.05x are possible. For speeds past 2x the tool chains two stages, so 3x is done as 2x then 1.5x.
Limitations
The range is 0.5x to 4x, and there is no way to change speed for only part of the file. Output follows the input format family, so WAV stays WAV, FLAC stays FLAC, M4A, AAC and MP4 become M4A, OGG and Opus become OGG and anything else becomes MP3, which means lossy files are encoded again. Video files are reduced to their audio.
Privacy
Time-stretching happens inside a worker in your browser, and your file is not uploaded. What is downloaded is the processing engine, around 25 MB from a public CDN, not anything about your audio. The sped-up or slowed copy lives in page memory until you save it, and the original on your computer stays exactly as it was.
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