Audio Speed Changer
A free online audio speed changer. Speed up or slow down an MP3, WAV or M4A while keeping the original pitch, and download the result as an MP3. Runs in your browser with ffmpeg — your file is never uploaded.
How do I change the speed of an audio file?
To change audio speed, load your file, pick a speed — above 1x to speed up, below 1x to slow down — and press Change speed. The tool re-times the audio while keeping the original pitch (so it never sounds chipmunk-like or droning) and hands you an MP3. Speeding a lecture or podcast to 1.25x–1.5x saves time; slowing to 0.5x–0.75x helps for transcription or learning music. The range is 0.5x to 2x, which keeps quality clean. It reads almost any input (MP3, WAV, M4A, FLAC, Opus and more) and runs entirely on your device, so nothing is uploaded. Want to change pitch without changing speed instead? Use the Audio Pitch Shifter. Want a fixed loudness boost instead? Use the Volume Booster; to cut a section first, the MP3 Trimmer.
Frequently Asked Questions
How do I speed up or slow down an audio file?
Load your audio file, choose a speed — for example 1.5x to make it faster or 0.75x to make it slower — and press Change speed. The tool re-times the audio and gives you the result as an MP3 to download. Everything runs on your device, so nothing is uploaded. Speeding up a lecture or podcast to 1.25x or 1.5x is a common way to save time; slowing to 0.5x or 0.75x helps for transcription or learning a piece of music.
Does changing the speed change the pitch?
No — changing the speed does not change the pitch. This tool changes the tempo while keeping the original pitch, so a faster version does not sound high-pitched or chipmunk-like and a slower version does not sound deep or droning — voices and music stay natural, just faster or slower. This is different from simply playing a record faster, which raises the pitch; here the pitch is preserved so the result sounds like the same speaker or instrument at a different pace.
What speed range is available?
You can set the speed from 0.5x (half speed) up to 2x (double speed), which covers essentially every everyday need — from slowing music down to learn it, to speeding up long recordings. Very large changes reduce quality because there is only so much the tempo can be stretched before artifacts appear, so extreme speeds are intentionally not offered; 0.5x to 2x keeps the result clean and natural. The dropdown offers 0.5x, 0.75x, 1.25x, 1.5x, 1.75x and 2x as quick presets, so you rarely need to reach for a middle value.
Is my audio uploaded, and what format do I get back?
Nothing is uploaded — the speed change runs entirely in your browser with ffmpeg compiled to WebAssembly, and the engine downloads once (about 10 MB) then later runs start instantly. The result is saved as an MP3 at the bitrate you choose, which plays everywhere; if you need another format, run the MP3 through the Audio Converter. Your original file and the sped-up or slowed-down result never leave your device, so it works offline after that first load and there is nothing to sign up for.
Will a faster file be shorter?
Yes — the duration changes in proportion to the speed. At 2x a ten-minute recording becomes five minutes; at 0.5x it becomes twenty minutes. The file size roughly follows the new duration at the bitrate you choose. This is exactly what you want for fitting a long talk into less time, or stretching a passage out to study it closely.