Note to Frequency Calculator
Convert musical notes to their frequency in Hz, or enter a frequency to find the nearest musical note.
Based on A4 = 440 Hz standard tuning.
Frequency / Note
Musical note frequencies are based on the equal temperament tuning system, where each octave is divided into 12 equal semitones.
Note to Frequency:
f = 440 × 2^((n - 49) / 12)
Where n is the key number (A4 = key 49 on a piano).
Frequency to Note:
n = 12 × log2(f / 440) + 49
Reference frequencies (A4 = 440 Hz):
- C4 (Middle C): 261.63 Hz
- D4: 293.66 Hz
- E4: 329.63 Hz
- F4: 349.23 Hz
- G4: 392.00 Hz
- A4: 440.00 Hz
- B4: 493.88 Hz
- C5: 523.25 Hz
Octave relationships:
- Each octave doubles the frequency
- A3 = 220 Hz, A4 = 440 Hz, A5 = 880 Hz
This calculator supports both directions:
- Select a note and octave to get its frequency
- Enter a frequency in Hz to find the nearest note