Free tool
Audio Speed Changer
Slow a part down to learn it, or move a loop to your project tempo — with the pitch held in place or allowed to move like tape.
Stretching happens in this browser tab. Your audio is never uploaded and never stored.
Choose the file to speed up or slow down
WAV, MP3, FLAC, AIFF, M4A, OGG — up to 250 MB.
Detail
How this works
There are two honest ways to change speed. Varispeed resamples: it is mathematically exact and sounds like a record at the wrong RPM, because pitch and tempo are the same thing when you change the playback rate. Time stretching splits them apart by re-laying overlapping slices of the waveform, which keeps the pitch but is always an approximation.
This tool uses waveform-similarity overlap-add, which searches for the best matching position for each slice before it writes it. That is why moderate changes hold together and extreme ones do not: there is no way to invent the material a large stretch needs.
To hit a specific tempo, work out the factor first — target BPM divided by original BPM — with the tempo calculator, then render it here.
FAQ
Frequently asked questions
Toolbox
Related tools
Train your sound. Generate your song.
ANYANO is the bigger version of this: prepare music you own, train a Sound that stays private to your account, then generate from it.