Preview, measure, and export in one place
Audio Speed Changer
Your file is processed in this browser and never uploaded. Pitch preservation is on by default.
Preview uses your browser's pitch-preserving playback. Export uses local time stretching and may take a moment.
Files this tempo changer can open
Choose one MP3, WAV, FLAC, AAC, OGG, or M4A file. Actual decoding support comes from your browser; current Chrome and Edge can read these formats.
The file stays on your device. There is no account, upload queue, or server copy.
Change music speed and see the new BPM
Move the control anywhere from 0.25× to 4×. The page first estimates the original tempo, then multiplies that estimate by your selected speed to show the new BPM.
This makes it quick to change the tempo of a song for practice, dance rehearsal, transcription, or a faster review. The BPM remains an estimate and can land on a half-time or double-time interpretation.
What happens at extreme speeds
Pitch-preserving time stretching repositions short pieces of the waveform. Near 0.25× or 4×, drums and other sharp transients may sound slightly smeared or metallic. Smaller changes usually sound cleaner.
Preview before exporting. The download is a 16-bit PCM WAV file, regardless of the input format.
Audio speed changer FAQ
Can I slow down music without changing its key?
Yes. Pitch preservation is enabled for both preview and export, so the speed changes while the musical pitch stays close to the original.
Can I change the speed of an MP3?
Yes. Choose an MP3, set the speed, preview it, and export the result as a WAV file.
How do I change the tempo of a song?
Load one audio file and move the speed slider. Values below 1× slow down music; values above 1× make it faster.
Does the audio leave my device?
No. Decoding, BPM estimation, preview, time stretching, and WAV creation all run inside this browser tab.