Exact Hz for every musical note — full piano range
Note
Octave
Reference pitch — A4 =
Hz
440.00 Hz
A4 — Concert pitch A
MIDI 69 · Wavelength 78.41 cm
Same note across octaves — click any to select
Frequency table
Highlight:
Note
Freq (Hz)
MIDI
Wavelength
Enharmonic
Frequently asked questions
What frequency is middle C?
Middle C (C4) has a frequency of 261.63 Hz at standard concert pitch (A4 = 440 Hz). It sits roughly in the middle of a standard 88-key piano keyboard and is MIDI note 60.
What is A4 440 Hz?
A4 440 Hz is the internationally agreed concert pitch standard — the A note above middle C vibrates at exactly 440 cycles per second. This is used to tune orchestras and instruments worldwide, established as the ISO 16 standard in 1955.
How is note frequency calculated?
Note frequency uses the formula f = A4 × 2^((n−69)/12), where n is the MIDI note number. Each octave doubles the frequency, and each semitone multiplies frequency by the 12th root of 2 (≈ 1.05946).
What is the difference between 432 Hz and 440 Hz tuning?
432 Hz and 440 Hz refer to the reference pitch of A4. Standard concert pitch is 440 Hz. Some musicians prefer 432 Hz, claiming it sounds warmer or more natural, though scientific evidence for perceptual differences is limited. Use the reference pitch selector above to compare both.