Varispeed Calculator
Varispeed changes speed and pitch together, like tape or a turntable. Type a speed percentage, a number of semitones or the BPM you want, and the other values follow.
How to use the varispeed calculator
- Type the song's original BPM, or find it first with the BPM Finder.
- Type the speed percentage, the semitones, or the new BPM you want.
- Read the other values: speed, pitch change in semitones and cents, and the new tempo.
- To hear it, load the song into the Pitch Changer in Varispeed mode and set the same amount.
The varispeed formula
Varispeed plays audio faster or slower without any time stretching, so pitch and tempo move together by the same ratio. Semitones equal 12 times the base 2 logarithm of the speed ratio, and the new BPM is the old BPM times the ratio.
That means 100 percent is no change, about 105.9 percent is one semitone up, about 94.4 percent is one semitone down, 200 percent is a full octave up and 50 percent a full octave down. Every semitone is a 5.95 percent step, compounding.
Common varispeed settings
Slowed edits usually sit around 80 to 90 percent, which drops the pitch by about two to four semitones. Nightcore runs about 120 to 130 percent. DJs nudging a track to match another usually stay within plus or minus 8 percent, roughly one and a third semitones either way.
Record players are varispeed too. Playing a 33 rpm record at 45 is 135 percent, a little over five semitones up, and playing a 45 at 33 is about 74 percent, a little over five semitones down.
Varispeed vs pitch shift vs time stretch
Varispeed changes speed and pitch together and adds no artifacts, which is why tape and vinyl sound so natural when sped up or slowed down. Pitch shifting changes the key but keeps the tempo, and time stretching changes the tempo but keeps the key. Both of those need processing that can leave small artifacts on big moves.
The free Pitch Changer does all three. Use Varispeed mode for the tape sound, Pitch mode to change key only, or Speed mode to change tempo only.
Varispeed calculator: common questions
How many semitones is 10 percent faster?
About 1.65 semitones up. A speed of 110 percent equals 12 times log base 2 of 1.1, which is 1.65 semitones, or 165 cents.
What speed is one semitone?
About 105.95 percent to go up one semitone and about 94.39 percent to go down one.
What is varispeed?
Varispeed changes playback speed and pitch together, like speeding up a tape or a turntable. Nothing is time stretched, so it sounds natural.
How do I apply varispeed to a song?
Open the free Pitch Changer, choose Varispeed mode, and set the same semitones or speed shown here. It runs in your browser and exports a WAV.
Is the varispeed calculator free?
Yes, free with no sign-up. It runs in your browser and works offline once the page has loaded.
Who makes this?
We're the small team behind Xport Studio, a private, fully offline app for AI vocals, stems, and mastering. These free tools run on the same idea: your audio stays on your device. If you're curious about the bigger thing, take a look.