Is the MP3 speed changer free?
Yes. Speeding up or slowing down an MP3 is completely free, with no signup.
Does it upload my MP3?
No. The speed change and export run locally in your browser, so your file stays on your device.
Can I use a custom multiplier?
Yes. The tool includes preset speeds and a custom multiplier field so you can set the exact playback rate you want.
Is it mainly for spoken audio?
Usually yes. It is ideal for lectures and classes, but it can be used for any MP3 where a simple speed change is enough.
Does it work on mobile?
Yes. Because it runs in the browser, you can change MP3 speed on a phone or tablet as well as a desktop.
How do I speed up an MP3?
Open the MP3 here, pick a speed preset such as 1.25x or 1.5x, and export. The audio is time-stretched in your browser, so the pitch stays exactly where it was and the file is never uploaded.
How do I slow down an MP3 without changing the pitch?
Choose 0.75x or 0.5x. The tool time-stretches the audio instead of resampling it, so a slowed-down recording keeps the speaker's natural pitch. That is what makes it usable for transcription and language practice.
Will speeding up the audio make the voice sound higher?
No. Simply playing a file faster does raise the pitch, but that is not what happens here: the audio is time-stretched, so a lecture at 1.5x still sounds like the same person, just faster.
Does changing the speed make the file smaller?
Yes, in proportion to the time saved. A 60-minute podcast at 1.5x becomes 40 minutes of audio at the same bitrate, so the MP3 shrinks by roughly a third.
What speed is best for a podcast or a lecture?
1.25x or 1.5x for most spoken audio. Comprehension usually falls off past 2x, and since the content is the same length either way, pushing the speed further tends to cost more than it saves.