Speed Up or Slow Down an Audio File
Speed up or slow down an audio file, 0.5× to 2× — in your browser.
Select an audio file
Speed up or slow down an audio file — 0.5× to 2×. Pitch changes with speed. Runs in your browser.
Click to choose, or drop a file here
You can also paste (Ctrl+V / Cmd+V)
Most tools run entirely on your device
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About changing audio speed
Slowing audio down makes a lecture or a language recording easier to follow and transcribe; speeding it up gets through a podcast or audiobook faster. This tool changes the speed of any common audio file, 0.5× to 2×, in your browser.
"Keep pitch" is on by default: it time-stretches the audio with a WSOLA algorithm so a voice stays the same pitch at 1.5× or 0.75×, the way podcast apps do it. Untick it and the tool resamples instead — pitch moves with speed, faster is higher and slower is lower, which is the classic "nightcore" / "slowed + reverb" effect and the behaviour of a record at the wrong RPM.
The whole file is decoded into memory and re-encoded to MP3 or WAV, so very long recordings depend on your device's RAM. Nothing is uploaded at any point.
Supported files
Accepts MP3, WAV, M4A, AAC, FLAC or OGG. Produces an MP3 or WAV at the new speed.
Is my file uploaded?
No. The audio is decoded, time-stretched or resampled, and re-encoded entirely in your browser.
Common problems
- The voice sounds like a chipmunk / too deep
- Turn on "Keep pitch" — that time-stretches instead of resampling, so the pitch stays put.
- "Keep pitch" sounds a bit warbly on music
- Time-stretching always adds some artefacts, more on dense music than on speech. For a clean result, untick it and accept the pitch shift.
How to Change Audio Speed
- 1
Add your audio
Drop in the clip whose speed you want to change.
- 2
Set the speed
0.5× to 2×. "Keep pitch" is on by default; untick it for the pitch-shift (nightcore) effect.
- 3
Apply and download
Click Change speed and save the result.
Change Audio Speed — frequently asked questions
Does the pitch change?+
Not by default. "Keep pitch" is on, which time-stretches the audio so a voice stays natural at any speed. Untick it to resample instead — then pitch moves with speed (the nightcore / slowed effect).
How far can I go?+
0.5× to 2×.
Is my file uploaded?+
No. The speed change is computed entirely in your browser.
Why does "Keep pitch" sound slightly warbly?+
Time-stretching rearranges short overlapping grains of audio, which adds mild artefacts — usually fine on speech, more noticeable on busy music. Untick it for an artefact-free result with a pitch shift.
Do you upload my files to a server?+
No — every tool here processes your files entirely on your device, and nothing is uploaded to a server. The only exception is the AI tools, which send the extracted text (not the file) to Claude to do their work.
Is there a file size limit?+
There's no artificial limit we impose, but since processing happens in your browser, very large files (500+ MB or 1,000+ pages) are limited by your device's memory rather than by us.
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