Free Note Frequency Table Online | Instant & Private

Filter by note, octave, or MIDI number

MIDI	Note	Frequency (Hz)	Wavelength (m)
21	A0	27.50	12.364
22	A#0	29.14	11.670
23	B0	30.87	11.015
24	C1	32.70	10.397
25	C#1	34.65	9.813
26	D1	36.71	9.262
27	D#1	38.89	8.742
28	E1	41.20	8.252
29	F1	43.65	7.789
30	F#1	46.25	7.351
31	G1	49.00	6.939
32	G#1	51.91	6.549
33	A1	55.00	6.182
34	A#1	58.27	5.835
35	B1	61.74	5.507
36	C2	65.41	5.198
37	C#2	69.30	4.907
38	D2	73.42	4.631
39	D#2	77.78	4.371
40	E2	82.41	4.126
41	F2	87.31	3.894
42	F#2	92.50	3.676
43	G2	98.00	3.469
44	G#2	103.83	3.275
45	A2	110.00	3.091
46	A#2	116.54	2.917
47	B2	123.47	2.754
48	C3	130.81	2.599
49	C#3	138.59	2.453
50	D3	146.83	2.316
51	D#3	155.56	2.186
52	E3	164.81	2.063
53	F3	174.61	1.947
54	F#3	185.00	1.838
55	G3	196.00	1.735
56	G#3	207.65	1.637
57	A3	220.00	1.545
58	A#3	233.08	1.459
59	B3	246.94	1.377
60	C4	261.63	1.300
61	C#4	277.18	1.227
62	D4	293.66	1.158
63	D#4	311.13	1.093
64	E4	329.63	1.031
65	F4	349.23	0.974
66	F#4	369.99	0.919
67	G4	392.00	0.867
68	G#4	415.30	0.819
69	A4	440.00	0.773
70	A#4	466.16	0.729
71	B4	493.88	0.688
72	C5	523.25	0.650
73	C#5	554.37	0.613
74	D5	587.33	0.579
75	D#5	622.25	0.546
76	E5	659.26	0.516
77	F5	698.46	0.487
78	F#5	739.99	0.459
79	G5	783.99	0.434
80	G#5	830.61	0.409
81	A5	880.00	0.386
82	A#5	932.33	0.365
83	B5	987.77	0.344
84	C6	1046.50	0.325
85	C#6	1108.73	0.307
86	D6	1174.66	0.289
87	D#6	1244.51	0.273
88	E6	1318.51	0.258
89	F6	1396.91	0.243
90	F#6	1479.98	0.230
91	G6	1567.98	0.217
92	G#6	1661.22	0.205
93	A6	1760.00	0.193
94	A#6	1864.66	0.182
95	B6	1975.53	0.172
96	C7	2093.00	0.162
97	C#7	2217.46	0.153
98	D7	2349.32	0.145
99	D#7	2489.02	0.137
100	E7	2637.02	0.129
101	F7	2793.83	0.122
102	F#7	2959.96	0.115
103	G7	3135.96	0.108
104	G#7	3322.44	0.102
105	A7	3520.00	0.097
106	A#7	3729.31	0.091
107	B7	3951.07	0.086
108	C8	4186.01	0.081

A4 = 440 Hz (standard tuning). Wavelength calculated using speed of sound = 340 m/s.

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FAQ

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How it works

The Note Frequency Table provides a complete reference for all 88 piano keys (MIDI notes 21–108, from A0 to C8) — displaying each note's name, octave, frequency in Hz, and wavelength in meters. Use it as a synthesis reference, a tuning calibration resource, a physics study aid, or a quick lookup when setting oscillator frequencies in a synthesizer or sample library.

Frequency formula: each note's frequency is calculated as A4_freq × 2^((midi − 69) / 12), where A4 = 440 Hz (standard tuning, ISO 16). This formula defines equal temperament — the modern Western tuning system where each semitone is the same frequency ratio (2^(1/12) ≈ 1.05946).

Wavelength calculation: wavelength = speed of sound / frequency. Speed of sound in air at 20°C is approximately 340 m/s (varies slightly with temperature and humidity). The lowest piano note A0 (27.5 Hz) has a wavelength of approximately 12.4 meters — longer than a school bus. C8 (4186 Hz) has a wavelength of approximately 8 cm.

Notable frequencies: - A4 = 440 Hz — international tuning reference - A3 = 220 Hz — one octave below A4 - C4 (Middle C) = 261.63 Hz — geometric center of the piano keyboard - A0 = 27.5 Hz — lowest piano key - C8 = 4186 Hz — highest piano key

Filtering: type a note name (A, C#, Bb), an octave number (4), or a MIDI number (69) in the filter box to narrow the table. The A-natural rows are highlighted in blue for quick octave orientation.

Equal temperament vs just intonation: this table uses equal temperament (ET). Just intonation uses pure whole-number ratios for intervals, producing slightly different frequencies for most notes (except the octave). ET is universal in modern instruments; just intonation is used in some vocal and microtonal contexts.

Privacy: all frequency data is pre-calculated and displayed locally with no network requests.

Frequently Asked Questions

Why is A4 = 440 Hz and not some round number?

440 Hz was chosen as the international standard (ISO 16, 1975) as a practical compromise among different national standards. Before standardization, A4 ranged from 415 Hz (Baroque) to 452 Hz (some 19th century orchestras). 440 Hz was common in American broadcasting and recording from the 1930s. Equal temperament makes it impossible for all notes to be round numbers simultaneously — if A4 = 440, then C4 = 261.63 Hz. There is no equal-temperament tuning where all 88 piano notes are integers.

What is the lowest and highest note a human can hear?

Human hearing ranges approximately from 20 Hz to 20,000 Hz, though the upper limit decreases significantly with age. The lowest piano note, A0, is 27.5 Hz — near the lower boundary of comfortable hearing. The highest piano note, C8, is 4186 Hz — well within the hearing range for most people. Notes above approximately C7 (2093 Hz) start to sound more like tones than distinct pitches to most listeners. The lowest notes of a pipe organ go below 16 Hz (pedal stops), below the threshold of pitch perception.

Why are A notes highlighted in blue?

A notes (A0 through A7) are highlighted because A4 = 440 Hz is the international tuning reference, and the A notes across all octaves are the natural reference points for tuning checks. Each A note is exactly a power-of-2 multiple of 27.5 Hz: A0=27.5, A1=55, A2=110, A3=220, A4=440, A5=880, A6=1760, A7=3520. This doubly-periodic pattern makes A notes the easiest to mentally verify.

What is the wavelength column for?

Wavelength = speed of sound / frequency. It shows the physical size of the sound wave in air (at 20°C, speed ≈ 340 m/s). Low notes have long wavelengths — A0 has a 12.4 m wavelength, explaining why bass frequencies pass through walls easily (the wavelength is longer than typical room dimensions, so diffraction is strong). High notes have short wavelengths — C8 is about 8 cm, similar to a hand-span, which is why treble frequencies are more directional and are blocked by obstacles.