4186.01Hz
Start with your device volume low. Very low tones may be inaudible on phone or laptop speakers; very high tones can be uncomfortable on headphones.
4.186 kHzFrequency at A4 = 440 Hz
108MIDI note number
88Piano key (of 88)
8.2 cmWavelength in air
About C8
C8 has a frequency of 4.186 kHz in standard tuning, where A4 is fixed at 440 Hz. It is MIDI note 108 and key number 88 on an 88-key piano.
C8 is the highest key on a standard 88-key piano.
In equal temperament every semitone multiplies the frequency by the twelfth root of two (≈1.05946), so C8 is 39 semitones above A4: f = 440 × 2^((108 − 69) / 12) = 4,186.01 Hz. The number in the name is the octave in scientific pitch notation, which starts each octave on C.
C8 frequency in different tunings
| Tuning reference | C8 frequency |
|---|---|
| A4 = 440 Hz (ISO 16 standard) | 4.186 kHz |
| A4 = 442 Hz (many European orchestras) | 4.205 kHz |
| A4 = 443 Hz (Berlin, Vienna) | 4.215 kHz |
| A4 = 435 Hz (French diapason normal, 1859) | 4.138 kHz |
| A4 = 432 Hz (alternative tuning) | 4.11 kHz |
| A4 = 415 Hz (Baroque pitch) | 3.948 kHz |
| C4 = 256 Hz (scientific pitch) | 4.096 kHz |
Intervals from C8
| Interval | Note | Frequency | Ratio (just) |
|---|---|---|---|
| Minor second | C♯8 | 4.435 kHz | 16:15 |
| Major second | D8 | 4.699 kHz | 9:8 |
| Minor third | D♯8 | 4.978 kHz | 6:5 |
| Major third | E8 | 5.274 kHz | 5:4 |
| Perfect fourth | F8 | 5.588 kHz | 4:3 |
| Tritone | F♯8 | 5.92 kHz | 45:32 |
| Perfect fifth | G8 | 6.272 kHz | 3:2 |
| Minor sixth | G♯8 | 6.645 kHz | 8:5 |
| Major sixth | A8 | 7.04 kHz | 5:3 |
| Minor seventh | A♯8 | 7.459 kHz | 9:5 |
| Major seventh | B8 | 7.902 kHz | 15:8 |
| Octave | C9 | 8.372 kHz | 2:1 |
Instruments and voices that can play C8
Frequently asked questions
What is the frequency of C8?
C8 is 4.186 kHz when A4 = 440 Hz (4.11 kHz if A4 = 432 Hz).
What MIDI number is C8?
C8 is MIDI note number 108.
Is C8 on a piano?
Yes – it is key 88 of 88.