This is a virtual keyboard showing the absolute frequencies in hertz

Hertz

The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....

 (cycles per second) of the notes on a modern piano

Piano

The piano is a musical instrument played by means of a keyboard. It is one of the most popular instruments in the world. Widely used in classical and jazz music for solo performances, ensemble use, chamber music and accompaniment, the piano is also very popular as an aid to composing and rehearsal...

 (typically containing 88 keys) in twelve-tone equal temperament, with the 49th key, the fifth A (called A4), tuned to 440 Hz (referred to as A440). Each successive pitch is derived by multiplying (ascending) or dividing (descending) the previous by the twelfth root of two (approximately 1.05946309435929...). For example, to get the frequency

Frequency

Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...

 a semitone

Semitone

A semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant when sounded harmonically....

 up from A4 (A4), multiply 440 by the twelfth root of two. To go from A4 to B4 (up a whole tone, or two semitones), multiply 440 twice by the twelfth root of two. For other tuning schemes refer to musical tuning

Musical tuning

In music, there are two common meanings for tuning:* Tuning practice, the act of tuning an instrument or voice.* Tuning systems, the various systems of pitches used to tune an instrument, and their theoretical bases.-Tuning practice:...

.

This list of frequencies is for a theoretically ideal piano. On an actual piano the ratio between semitones is slightly larger, especially at the high and low ends, where string stiffness causes inharmonicity

Inharmonicity

In music, inharmonicity is the degree to which the frequencies of overtones depart from whole multiples of the fundamental frequency....

, i.e., the tendency for the harmonic

Harmonic

A harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency, i.e. if the fundamental frequency is f, the harmonics have frequencies 2f, 3f, 4f, . . . etc. The harmonics have the property that they are all periodic at the fundamental...

 makeup of each note to run sharp

Sharp (music)

In music, sharp, dièse , or diesis means higher in pitch and the sharp symbol raises a note by a half tone. Intonation may be flat, sharp, or both, successively or simultaneously...

. To compensate for this, octaves are tuned slightly wide, stretched according to the inharmonic characteristics of each instrument. This deviation from equal temperament is called the Railsback curve.

The following equation will give the frequency f of the n^th key, as shown in the table:

Alternatively, this can be written as:

Virtual keyboard

Key number	Helmholtz Helmholtz pitch notation Helmholtz pitch notation is a musical system for naming notes of the Western chromatic scale. Developed by the German scientist Hermann von Helmholtz, it uses a combination of upper and lower case letters , and the sub- and super-prime symbols to describe each individual note of the scale... name	Scientific Scientific pitch notation Scientific pitch notation is one of several methods that name the notes of the standard Western chromatic scale by combining a letter-name, accidentals, and a number identifying the pitch's octave... name	Frequency (Hz)	Corresponding Open Strings
				Violin Violin The violin is a string instrument, usually with four strings tuned in perfect fifths. It is the smallest, highest-pitched member of the violin family of string instruments, which includes the viola and cello....	Viola Viola The viola is a bowed string instrument. It is the middle voice of the violin family, between the violin and the cello.- Form :The viola is similar in material and construction to the violin. A full-size viola's body is between and longer than the body of a full-size violin , with an average...	Cello Cello The cello is a bowed string instrument with four strings tuned in perfect fifths. It is a member of the violin family of musical instruments, which also includes the violin, viola, and double bass. Old forms of the instrument in the Baroque era are baryton and viol .A person who plays a cello is...	Bass Double bass The double bass, also called the string bass, upright bass, standup bass or contrabass, is the largest and lowest-pitched bowed string instrument in the modern symphony orchestra, with strings usually tuned to E1, A1, D2 and G2...	Guitar Guitar The guitar is a plucked string instrument, usually played with fingers or a pick. The guitar consists of a body with a rigid neck to which the strings, generally six in number, are attached. Guitars are traditionally constructed of various woods and strung with animal gut or, more recently, with...
88	c′′′′′ 5-line octave Octave In music, an octave is the interval between one musical pitch and another with half or double its frequency. The octave relationship is a natural phenomenon that has been referred to as the "basic miracle of music", the use of which is "common in most musical systems"...	C8 Eighth octave C The musical note C8 is the C two full octaves above soprano high C. The note is one octave above the top of common musical keyboards, but the highest note of an 88-key piano...  Eighth octave	4186.01
87	b′′′′	B7	3951.07
86	a′′′′/b′′′′	A7/B7	3729.31
85	a′′′′	A7	3520.00
84	g′′′′/a′′′′	G7/A7	3322.44
83	g′′′′	G7	3135.96
82	f′′′′/g′′′′	F7/G7	2959.96
81	f′′′′	F7	2793.83
80	e′′′′	E7	2637.02
79	d′′′′/e′′′′	D7/E7	2489.02
78	d′′′′	D7	2349.32
77	c′′′′/d′′′′	C7/D7	2217.46
76	c′′′′ 4-line octave	C7 Double high C	2093.00
75	b′′′	B6	1975.53
74	a′′′/b′′′	A6/B6	1864.66
73	a′′′	A6	1760.00
72	g′′′/a′′′	G6/A6	1661.22
71	g′′′	G6	1567.98
70	f′′′/g′′′	F6/G6	1479.98
69	f′′′	F6	1396.91
68	e′′′	E6	1318.51
67	d′′′/e′′′	D6/E6	1244.51
66	d′′′	D6	1174.66
65	c′′′/d′′′	C6/D6	1108.73
64	c′′′ 3-line octave	C6 Soprano C (High C)	1046.50
63	b′′	B5	987.767
62	a′′/b′′	A5/B5	932.328
61	a′′	A5	880.000
60	g′′/a′′	G5/A5	830.609
59	g′′	G5	783.991
58	f′′/g′′	F5/G5	739.989
57	f′′	F5	698.456
56	e′′	E5	659.255	E
55	d′′/e′′	D5/E5	622.254
54	d′′	D5	587.330
53	c′′/d′′	C5/D5	554.365
52	c′′ 2-line octave	C5 Tenor C	523.251
51	b′	B4	493.883
50	a′/b′	A4/B4	466.164
49	a′	A4 A440	440.000	A	A
48	g′/a′	G4/A4	415.305
47	g′	G4	391.995
46	f′/g′	F4/G4	369.994
45	f′	F4	349.228
44	e′	E4	329.628					High E
43	d′/e′	D4/E4	311.127
42	d′	D4	293.665	D	D
41	c′/d′	C4/D4	277.183
40	c′ 1-line octave	C4 Middle C Middle C C or Do is the first note of the fixed-Do solfège scale. Its enharmonic is B.-Middle C:Middle C is designated C4 in scientific pitch notation because of the note's position as the fourth C key on a standard 88-key piano keyboard...	261.626
39	b	B3	246.942					B
38	a/b	A3/B3	233.082
37	a	A3	220.000			A
36	g/a	G3/A3	207.652
35	g	G3	195.998	G	G			G
34	f/g	F3/G3	184.997
33	f	F3	174.614
32	e	E3	164.814
31	d/e	D3/E3	155.563
30	d	D3	146.832			D		D
29	c/d	C3/D3	138.591
28	c small octave	C3 Low C	130.813		C
27	B	B2	123.471
26	A/B	A2/B2	116.541
25	A	A2	110.000					A
24	G/A	G2/A2	103.826
23	G	G2	97.9989			G	G
22	F/G	F2/G2	92.4986
21	F	F2	87.3071
20	E	E2	82.4069					Low E
19	D/E	D2/E2	77.7817
18	D	D2	73.4162				D
17	C/D	C2/D2	69.2957
16	C great octave	C2 Deep C	65.4064			C
15	B͵	B1	61.7354
14	A͵/B͵	A1/B1	58.2705
13	A͵	A1	55.0000				A
12	G͵/A͵	G1/A1	51.9131
11	G͵	G1	48.9994
10	F͵/G͵	F1/G1	46.2493
9	F͵	F1	43.6535
8	E͵	E1	41.2034				E
7	D͵/E͵	D1/E1	38.8909
6	D͵	D1	36.7081
5	C͵/D͵	C1/D1	34.6478
4	C͵ contra-octave	C1 Pedal C	32.7032
3	B͵͵	B0	30.8677				B (5-string)
2	A͵͵/B͵͵	A0/B0	29.1352
1	A͵͵ sub-contra-octave	A0 Double Pedal A	27.5000

External links

• interactive piano frequency table — A php script allowing the reference pitch of A4 to be altered from 440 Hz.
• PySynth — A simple Python
  Python (programming language)
  Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...
  
  -based software synthesizer
  Software synthesizer
  A software synthesizer, also known as a softsynth is a computer program or plug-in for digital audio generation. Computer software which can create sounds or music is not new, but advances in processing speed are allowing softsynths to accomplish the same tasks that previously required dedicated...
  
  that prints the key frequencies table and then creates a few demo songs based on that table.