Need to slow down a fast-talking lecture so you can actually take notes, or speed up a two-hour podcast to get through it on your commute? This audio speed changer lets you dial in any playback speed from a quarter speed up to double, preview it instantly, and export the result as MP3 or WAV. It runs entirely in your browser, so the file never leaves your device.

How to change the speed of an audio file

Drop in a file and the speed controls appear. Drag the slider anywhere between 0.25x and 2x, or tap one of the quick presets (0.5x, 0.75x, 1.25x, 1.5x, 2x) to jump straight to a common value. The number above the slider updates live, and so does the “New Duration” box, so you always know how long the result will run before you commit to anything.

Hit Preview to hear the change before downloading. Once it sounds right, pick MP3 or WAV under Export As and click Change Speed & Download. The file that comes out matches exactly what you heard in the preview.

Preserving pitch vs. the classic vinyl effect

This is where most simple speed tools cut corners, so it’s worth understanding the toggle.

With Preserve Pitch turned on, the tool re-times the audio using a grain-based stretching technique, splitting the waveform into small overlapping windows and repositioning them to fit the new duration. The result plays faster or slower without the voice turning into a chipmunk or a monster. This is what you want for lectures, podcasts, interviews, or any spoken content where you need to change the pace but keep it sounding like a normal human voice.

Turn the toggle off and you get the old-school effect: the audio is resampled directly, exactly like speeding up or slowing down a vinyl record or a tape reel. Pitch rises with speed and drops when you slow things down. It’s a fun effect for music remixes, sound design, or that deliberately warped, nostalgic sound, but it’s usually not what you want for spoken word.

Picking the right speed for the job

For learning material, most people find 1.25x to 1.5x speeds up consumption without losing comprehension, especially with Preserve Pitch on. Language learners often do the opposite: slowing dialogue down to 0.75x or even 0.5x makes it much easier to catch individual words and pronunciation.

Podcasts and audiobooks are usually fine anywhere between 1.25x and 1.75x once your ear adjusts. Transcriptionists tend to prefer slowing interviews down to 0.75x so they can type along in real time. And if you’re just experimenting with a sample or a vocal for a music project, the full 0.25x to 2x range with Preserve Pitch off opens up some genuinely strange and useful textures.

Choosing MP3 or WAV for the export

MP3 keeps the file small and plays everywhere, which makes it the practical choice for podcasts, voice notes, and lecture recordings you want to keep around or share. Pick a bitrate that fits the source: 128 kbps is plenty for speech, 192 kbps is a safe middle ground, and 320 kbps is worth it if the source material has music or you’re picky about quality.

WAV skips compression entirely and keeps every sample exactly as processed. Reach for it if you’re feeding the result into an editor, a DAW, or any workflow where you don’t want a second layer of lossy encoding stacked on top of the speed change.

Your file stays on your device

Everything, decoding, stretching or resampling, and re-encoding, happens locally using your browser’s Web Audio API. Nothing is uploaded to a server at any point, which matters if you’re processing a private interview, a personal voice memo, or anything else you’d rather keep off the internet.

Because the processing runs on your own machine, longer files take a bit more time to decode and stretch than short clips, and enabling Preserve Pitch is more computationally involved than a straight resample. For most podcast episodes and lecture recordings, though, both finish in well under a minute.

Need to trim a clip before changing its speed? The Audio Cutter lets you select and export just the section you need. If you’re converting between formats instead, the Audio Converter handles that without touching playback speed. And if the file is oversized to begin with, run it through the Audio Compressor first.