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Piano Note Frequency Finder
Interactive 88-key piano keyboard showing the exact frequency in Hz for every key from A0 to C8. Click any key to hear it, search by note name or frequency, and explore the full reference table.
Hz
A4 = 440.0 Hz
88-Key Piano Keyboard (A0 – C8)
Scroll horizontally to see all 88 keys →
Click any piano key or table row to see detailed note information
Complete 88-Key Reference Table
| Key # | Note | Octave | Frequency (Hz) | MIDI # | Period (ms) | Wavelength (m) | Play | Copy |
|---|
Piano Frequency Formula
Frequency Formula
f = 440 × 2(n − 69) / 12
Where f is the frequency in Hz, 440 is the A4 reference frequency, n is the MIDI note number (A4 = 69), and the exponent divides the octave into 12 equal semitones. Each semitone multiplies the frequency by 21/12 ≈ 1.05946.
Piano Key to MIDI
MIDI = key + 20
Piano key number 1 (A0) corresponds to MIDI note 21. Key 88 (C8) corresponds to MIDI 108. The standard 88-key piano covers a range of just over 7 octaves from 27.5 Hz to 4186 Hz.
Period Calculation
T = 1000 / f
The period T (in milliseconds) is the inverse of the frequency. A0 at 27.5 Hz has a period of 36.36 ms, while C8 at 4186 Hz has a period of only 0.239 ms. Lower notes have longer periods.
Wavelength Calculation
λ = 343 / f
The wavelength λ (in metres) is the speed of sound (343 m/s at 20°C) divided by the frequency. A0 has a wavelength of 12.47 m, while C8 is only 0.082 m (8.2 cm). This affects how low and high notes behave acoustically in rooms.
How to Use This Tool
- Find any piano key's frequency — Scroll the interactive 88-key piano or use the search box to type a note name (like "C4" or "F#5") or a frequency (like "440" or "261"). The matching key highlights on the piano and in the table below.
- Click to play and explore — Click any key on the piano or any row in the table to hear a pure sine tone at that frequency. The info panel shows the note name, exact Hz to 3 decimal places, MIDI number, period, wavelength, and piano key number.
- Adjust the A4 reference — Use the slider to change A4 from the standard 440 Hz to any value between 415 and 450 Hz. All 88 frequencies recalculate instantly. Try 432 Hz for "Verdi tuning," 415 Hz for Baroque pitch, or 443 Hz for European orchestral tuning.
Frequently Asked Questions
What are the frequencies of all 88 piano keys?
A standard 88-key piano spans from A0 (27.500 Hz) to C8 (4186.009 Hz) in standard A440 tuning. The lowest key A0 is near the lower limit of human pitch perception, while the highest key C8 is well within the audible range. Each semitone multiplies the frequency by 2^(1/12), approximately 1.05946. This tool shows the exact frequency for all 88 keys.
What frequency is middle C on a piano?
Middle C (C4) is approximately 261.626 Hz in standard A440 tuning. It is piano key number 40 and MIDI note number 60. Middle C sits near the center of the 88-key piano keyboard and is the most commonly referenced note in music education. Its period is about 3.822 ms and its wavelength is about 1.311 m.
How do I find the frequency of a specific piano key?
Use the search box to type the note name (e.g., "F#5", "Bb3", "C4") or type a frequency value to find the closest matching key. You can also scroll the interactive piano keyboard and click any key, or browse the complete reference table below the piano. The formula is f = 440 * 2^((MIDI - 69) / 12), where MIDI = piano key number + 20.
What is the frequency range of a piano?
A standard 88-key piano covers from A0 (27.500 Hz) to C8 (4186.009 Hz), spanning just over 7 octaves. This range was chosen because it encompasses nearly the full range of musically useful pitches. Frequencies below A0 are perceived more as rumble than pitch, while frequencies above C8, though audible, have limited musical application.
Why does my piano sound different from A440?
Many factors affect a piano's tuning. Concert grands are often tuned to A441-A443 Hz for a brighter sound. Older pianos may have drifted from their original tuning. Some styles use A432 Hz ("Verdi tuning"). Additionally, piano tuners apply "stretch tuning" where extreme high and low notes are tuned slightly sharp or flat respectively to match the inharmonicity of real piano strings.
What is the relationship between piano key numbers and MIDI numbers?
Piano key numbers run from 1 (A0, the lowest key) to 88 (C8, the highest key). MIDI note numbers for the piano range from 21 (A0) to 108 (C8). The conversion is simple: MIDI = piano key number + 20. Middle C (C4) is piano key 40 and MIDI 60. MIDI numbers extend beyond the piano range (0-127) to cover instruments with wider ranges.