According to the MIDI specification, a MIDI file can have upto 128 distinct pitches/notes, where the lowest note is a C. The notes are numbered 0 to 127.
As mentioned, the lowest note is a C and this is assigned note number 0. The C# above it would have a note number of 1. The D note above that would have a note number of 2, etc.
The middle C is note number 60. The A note above middle C is note number 69 (440 Hz).
A "full-size" keyboard will usually have only 88 keys, where the lowest key being the low A (MIDI note number 21) and the highest key being the high C (MIDI note number 108).
The middle C is commonly designated C4 (4 is also the fourth octave) in scientific pitch notation and in musical studies because of the note's position as the fourth C key on a standard 88-key piano keyboard.
This MIDI maker will only use octave 0 - 8 (note number 12 - 119).
Here below an overview of all note numbers and its corresponding [frequency] in herz used by this tool. Middle C is note number 60.
| Note name | Octave 0 | Octave 1 | Octave 2 | Octave 3 | Octave 4 |
| Note number [Frequency in Hz] | |||||
| C | 12 [16.3516] |
24 [32.7032] |
36 [65.4064] |
48 [130.8128] |
60 [261.6256] |
| C#/Db | 13 [17.3239] |
25 [34.6478] |
37 [69.2957] |
49 [138.5913] |
61 [277.1826] |
| D | 14 [18.354] |
26 [36.7081] |
38 [73.4162] |
50 [146.8324] |
62 [293.6648] |
| D#/Eb | 15 [19.4454] |
27 [38.8909] |
39 [77.7817] |
51 [155.5635] |
63 [311.127] |
| E | 16 [20.6017] |
28 [41.2034] |
40 [82.4069] |
52 [164.8138] |
64 [329.6276] |
| F | 17 [21.8268] |
29 [43.6535] |
41 [87.3071] |
53 [174.6141] |
65 [349.2282] |
| F#/Gb | 18 [23.1247] |
30 [46.2493] |
42 [92.4986] |
54 [184.9972] |
66 [369.9944] |
| G | 19 [24.4997] |
31 [48.9994] |
43 [97.9989] |
55 [195.9977] |
67 [391.9954] |
| G#/Ab | 20 [25.9565] |
32 [51.9131] |
44 [103.8262] |
56 [207.6523] |
68 [415.3047] |
| A | 21 [27.5] |
33 [55] |
45 [110] |
57 [220] |
69 [440] |
| A#/Bb | 22 [29.1352] |
34 [58.2705] |
46 [116.5409] |
58 [233.0819] |
70 [466.1638] |
| B | 23 [30.8677] |
35 [61.7354] |
47 [123.4708] |
59 [246.9417] |
71 [493.8833] |
| Note name | Octave 5 | Octave 6 | Octave 7 | Octave 8 |
| Note number [Frequency in Hz] | ||||
| C | 72 [523.2511] |
84 [1046.5023] |
96 [2093.0045] |
108 [4186.009] |
| C#/Db | 73 [554.3653] |
85 [1108.7305] |
97 [2217.461] |
109 [4434.9221] |
| D | 74 [587.3295] |
86 [1174.6591] |
98 [2349.3181] |
110 [4698.6363] |
| D#/Eb | 75 [622.254] |
87 [1244.5079] |
99 [2489.0159] |
111 [4978.0317] |
| E | 76 [659.2551] |
88 [1318.5102] |
100 [2637.0205] |
112 [5274.0409] |
| F | 77 [698.4565] |
89 [1396.9129] |
101 [2793.8259] |
113 [5587.6517] |
| F#/Gb | 78 [739.9888] |
90 [1479.9777] |
102 [2959.9554] |
114 [5919.9108] |
| G | 79 [783.9909] |
91 [1567.9817] |
103 [3135.9635] |
115 [6271.927] |
| G#/Ab | 80 [830.6094] |
92 [1661.2188] |
104 [3322.4376] |
116 [6644.8752] |
| A | 81 [880] |
93 [1760] |
105 [3520] |
117 [7040] |
| A#/Bb | 82 [932.3275] |
94 [1864.655] |
106 [3729.3101] |
118 [7458.6202] |
| B | 83 [987.7666] |
95 [1975.5332] |
107 [3951.0664] |
119 [7902.1328] |
Here below an image of a grand staff with the most important octaves.
