What this tool does
Slow down audio opens the change speed tool with this setting ready, so you only choose your file and tap once.
Speed up a lecture or long voice note to save time, or slow down a song to learn the lyrics or dance steps. Keep the voice natural so it does not sound like a cartoon, or untick it for the classic sped-up sound.
How to use it
- Choose your audio file.
- Pick the speed.
- Keep the voice natural, or not.
- Tap Change speed and download.
Why 123ToolBox
Your files stay with youEverything happens inside your browser. Nothing is uploaded to us or anyone else.
Free, no watermarkEvery tool is free. Your result has no logo or watermark.
No sign-upOpen the page and use it. No account, no email.
Made for phonesWorks on cheap Android phones as well as laptops.
FastNo upload or download wait. Small files finish in seconds.
Exact resultsWhen a form says “under 20 KB”, you get under 20 KB.
Popular ways to use it
Questions people ask
How do I speed up audio without changing the pitch?
Keep “Keep the voice natural” ticked. The tool changes speed but keeps the same voice.
How do I make a slowed version of a song?
Pick 0.75× or 0.9× and untick “Keep the voice natural” for the deeper slowed sound.
Can I change the speed of a video’s sound?
Yes. Choose the video; you get its sound at the new speed.
Is my audio uploaded?
No. Everything happens inside your browser. Your file never leaves your device.