A frequency to note converter maps hertz to the nearest piano key, cents offset, and MIDI number. A4 can be 440 Hz or 432 Hz. The chart lists A0 through C8.
440 Hz is A4 when A4 is defined as 440. MIDI note 69. At A4 = 432 Hz, 440 Hz is about 32 cents sharp of A4. Formula: midi = 69 + 12 × log2(f / A4).
A4 itself is 440 Hz in this tuning.
Nearest note
A4 (0 ¢)
| Note | Hz | MIDI |
|---|---|---|
| A0 | 27.5 | 21 |
| A#0 | 29.14 | 22 |
| B0 | 30.87 | 23 |
| C1 | 32.7 | 24 |
| C#1 | 34.65 | 25 |
| D1 | 36.71 | 26 |
| D#1 | 38.89 | 27 |
| E1 | 41.2 | 28 |
| F1 | 43.65 | 29 |
| F#1 | 46.25 | 30 |
| G1 | 49 | 31 |
| G#1 | 51.91 | 32 |
| A1 | 55 | 33 |
| A#1 | 58.27 | 34 |
| B1 | 61.74 | 35 |
| C2 | 65.41 | 36 |
| C#2 | 69.3 | 37 |
| D2 | 73.42 | 38 |
| D#2 | 77.78 | 39 |
| E2 | 82.41 | 40 |
| F2 | 87.31 | 41 |
| F#2 | 92.5 | 42 |
| G2 | 98 | 43 |
| G#2 | 103.83 | 44 |
| A2 | 110 | 45 |
| A#2 | 116.54 | 46 |
| B2 | 123.47 | 47 |
| C3 | 130.81 | 48 |
| C#3 | 138.59 | 49 |
| D3 | 146.83 | 50 |
| D#3 | 155.56 | 51 |
| E3 | 164.81 | 52 |
| F3 | 174.61 | 53 |
| F#3 | 185 | 54 |
| G3 | 196 | 55 |
| G#3 | 207.65 | 56 |
| A3 | 220 | 57 |
| A#3 | 233.08 | 58 |
| B3 | 246.94 | 59 |
| C4 | 261.63 | 60 |
| C#4 | 277.18 | 61 |
| D4 | 293.66 | 62 |
| D#4 | 311.13 | 63 |
| E4 | 329.63 | 64 |
| F4 | 349.23 | 65 |
| F#4 | 369.99 | 66 |
| G4 | 392 | 67 |
| G#4 | 415.3 | 68 |
| A4 | 440 | 69 |
| A#4 | 466.16 | 70 |
| B4 | 493.88 | 71 |
| C5 | 523.25 | 72 |
| C#5 | 554.37 | 73 |
| D5 | 587.33 | 74 |
| D#5 | 622.25 | 75 |
| E5 | 659.26 | 76 |
| F5 | 698.46 | 77 |
| F#5 | 739.99 | 78 |
| G5 | 783.99 | 79 |
| G#5 | 830.61 | 80 |
| A5 | 880 | 81 |
| A#5 | 932.33 | 82 |
| B5 | 987.77 | 83 |
| C6 | 1046.5 | 84 |
| C#6 | 1108.73 | 85 |
| D6 | 1174.66 | 86 |
| D#6 | 1244.51 | 87 |
| E6 | 1318.51 | 88 |
| F6 | 1396.91 | 89 |
| F#6 | 1479.98 | 90 |
| G6 | 1567.98 | 91 |
| G#6 | 1661.22 | 92 |
| A6 | 1760 | 93 |
| A#6 | 1864.66 | 94 |
| B6 | 1975.53 | 95 |
| C7 | 2093 | 96 |
| C#7 | 2217.46 | 97 |
| D7 | 2349.32 | 98 |
| D#7 | 2489.02 | 99 |
| E7 | 2637.02 | 100 |
| F7 | 2793.83 | 101 |
| F#7 | 2959.96 | 102 |
| G7 | 3135.96 | 103 |
| G#7 | 3322.44 | 104 |
| A7 | 3520 | 105 |
| A#7 | 3729.31 | 106 |
| B7 | 3951.07 | 107 |
| C8 | 4186.01 | 108 |
Results can be wrong. This calculator is unofficial. Figures can be incomplete, rounded, or not updated. Use them at your own risk and check a tape, datasheet, ball band, or official chart before cutting, mixing, buying, or publishing. Limits of liability are in the terms of service.
C4 is MIDI 60, about 261.63 Hz at A4 = 440.
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Estimates recording size from bitrate and duration, or bitrate from a target size.
Publisher notes · reviewed 29 October 2026
midi = 69 + 12 × log2(f / A4). Cents are 100 × (midiFloat − round(midi)). A4 can be 440 or 432. The table is A0–C8. There is no microphone.
Switching A4 retunes every key. It is not a different note-name system.
C4 at 440
MIDI 60, about 261.63 Hz.
