Tempo & Pitch Shift Calculator
Calculate the relationship between BPM changes and musical pitch.
1. Calculate Pitch Shift from BPM Change
2. Calculate New BPM from Pitch Shift
Understanding the Relationship Between Tempo and Pitch
In the world of music production, particularly when working with analog hardware or "classic" sampling techniques (like those used on the MPC60 or SP-1200), changing the speed of a sample directly affects its pitch. This is known as "resampling" or "varispeed."
When you speed up a piece of audio, the waveform is compressed, resulting in a higher frequency (pitch). Conversely, slowing it down stretches the waveform, lowering the pitch. This calculator helps you determine exactly how many semitones a sample will shift when you change its BPM, or what your target BPM should be to reach a specific musical key.
The Mathematical Formulas
The relationship between tempo and pitch follows a logarithmic scale. Because an octave is a doubling of frequency, we use base-2 logarithms for our calculations:
- Pitch Shift (Semitones) = 12 × log2(New BPM / Old BPM)
- New BPM = Old BPM × 2 ^ (Semitones / 12)
- Percentage Change = ((New BPM – Old BPM) / Old BPM) × 100
Practical Examples
Example 1: Sampling a Breakbeat
Imagine you have a drum loop at 90 BPM. You want to speed it up to 95 BPM to match your project. Using the calculator, you will see that the pitch will increase by approximately 0.93 semitones (93 cents). This is nearly a full half-step sharp.
Example 2: Pitching Down for "Vibe"
If you have a vocal at 120 BPM and you pitch it down exactly 2 semitones to give it a deeper, "chopped and screwed" feel, your new tempo will be 106.91 BPM.
Why Producers Use This
Modern DAWs (Digital Audio Workstations) like Ableton Live or FL Studio often use "Time Stretching" algorithms that preserve pitch while changing tempo. However, many producers prefer the "Natural" or "Repitch" mode because it avoids digital artifacts and preserves the punchy transients of the original audio, much like a vinyl record being spun faster or slower.