Free tool
Note Frequency Calculator
Convert between note names, frequencies (Hz), MIDI numbers and cents in any tuning standard.
Interval between two frequencies
Formulas
- Frequency of MIDI note n:
f = A4 × 2^((n − 69) / 12) - MIDI note from frequency:
n = 69 + 12 × log2(f / A4) - Interval in cents:
c = 1200 × log2(f2 / f1)
Middle C is C4 (MIDI 60, 261.63 Hz at A4 = 440). For a full table see the note frequency chart and MIDI note numbers.