The frequency of every note from C0 to B8 in twelve-tone equal temperament, tuned to A4 = 440 Hz. Rows are notes, columns are octaves.
Note frequencies in hertz at A4 = 440 Hz
Note
Octave 0
Octave 1
Octave 2
Octave 3
Octave 4
Octave 5
Octave 6
Octave 7
Octave 8
C
16.35
32.70
65.41
130.81
261.63
523.25
1,046.50
2,093.00
4,186.01
C♯
17.32
34.65
69.30
138.59
277.18
554.37
1,108.73
2,217.46
4,434.92
D
18.35
36.71
73.42
146.83
293.66
587.33
1,174.66
2,349.32
4,698.64
D♯
19.45
38.89
77.78
155.56
311.13
622.25
1,244.51
2,489.02
4,978.03
E
20.60
41.20
82.41
164.81
329.63
659.26
1,318.51
2,637.02
5,274.04
F
21.83
43.65
87.31
174.61
349.23
698.46
1,396.91
2,793.83
5,587.65
F♯
23.12
46.25
92.50
185.00
369.99
739.99
1,479.98
2,959.96
5,919.91
G
24.50
49.00
98.00
196.00
392.00
783.99
1,567.98
3,135.96
6,271.93
G♯
25.96
51.91
103.83
207.65
415.30
830.61
1,661.22
3,322.44
6,644.88
A
27.50
55.00
110.00
220.00
440.00
880.00
1,760.00
3,520.00
7,040.00
A♯
29.14
58.27
116.54
233.08
466.16
932.33
1,864.66
3,729.31
7,458.62
B
30.87
61.74
123.47
246.94
493.88
987.77
1,975.53
3,951.07
7,902.13
How note frequencies work
Every octave doubles the frequency: A3 is 220 Hz, A4 is 440 Hz and A5 is 880 Hz. Equal temperament splits each octave into 12 equal steps, so each semitone up multiplies the frequency by the twelfth root of two, about 1.0595.
To find any note, count its semitones from A4 and use f = 440 × 2n/12, where n is that number of semitones (negative below A4). Middle C, nine semitones below A4, is 261.63 Hz.
Middle C (C4) is 261.63 Hz when A4 is tuned to 440 Hz.
What frequency is A4?
440 Hz, the international standard reference pitch. Some orchestras use 442 or 443 Hz, and some musicians prefer 432 Hz.
How do I calculate the frequency of a note?
Count the number of semitones n from A4 (negative below it) and calculate 440 × 2^(n/12). For example, C5 is 3 semitones above A4, so 440 × 2^(3/12) = 523.25 Hz.
What are the lowest and highest notes on a piano?
A standard 88-key piano goes from A0 at 27.50 Hz to C8 at 4,186.01 Hz.