Frequency to Note Calculator
This frequency to note calculator converts any Hz value to the nearest musical note name, octave, and cents deviation. A4 = 440 Hz (0 cents). C4 (middle C) ≈ 261.63 Hz. Enter any frequency to see the note name, MIDI number, and whether it is sharp or flat.
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Frequently Asked Questions
What note is 440 Hz?
440 Hz is A4 — the A above middle C. It is the international standard tuning reference (A440 or concert pitch), defined by ISO 16 since 1955. Guitar strings, orchestral instruments, and digital tuners all use 440 Hz as the reference for A4.
What note is 432 Hz?
432 Hz is approximately A4 minus 32 cents (slightly flat). It is not a standard musical note at equal temperament with A4=440. Some musicians prefer tuning to 432 Hz for aesthetic or spiritual reasons, but this is not supported by scientific evidence of audible benefit.
What note is middle C?
Middle C is C4 at approximately 261.63 Hz (with A4=440 Hz reference). It is MIDI note number 60 and sits in the middle of the piano keyboard. It is a common reference pitch for vocalists and instrumentalists.
How do you convert Hz to musical notes?
Use the formula: semitones from A4 = 12 × log₂(freq / 440). Round to the nearest integer to get the nearest note. The remainder in cents = 1200 × log₂(freq / nearest_note_freq). This calculator does all of that automatically.
What are cents in music?
Cents measure small pitch intervals. One semitone = 100 cents. Zero cents means perfectly in tune. Positive cents means the pitch is sharp (higher than the note), negative cents means flat (lower). Most human ears detect deviations of about 5–10 cents.
What is the lowest note a human can sing?
The lowest note recorded by a human singer is G-7 (approximately 0.189 Hz), achieved by singer Tim Storms. In more practical terms, trained bass singers reach E2 (82.4 Hz). The average male voice bottoms out around 80–100 Hz.
What frequency is the highest piano key?
The highest key on a standard 88-key piano is C8 at approximately 4,186 Hz. The lowest key is A0 at 27.5 Hz. The human hearing range is roughly 20 Hz to 20,000 Hz, so the piano covers much of the musically relevant range.
Why is 440 Hz the standard tuning?
A4=440 Hz was standardized by ISO in 1955 to allow instruments from different countries to play together in tune. Before standardization, tuning varied widely — Baroque pitch was often around A4=415 Hz. Some orchestras use A4=442 or 443 Hz for a slightly brighter sound.
How Frequency to Note Conversion Works
In equal temperament, notes are spaced so that each semitone is a fixed frequency ratio of 2^(1/12) ≈ 1.0595. The reference pitch is A4 = 440 Hz. Given any frequency, we calculate its distance from A4 in semitones, round to the nearest semitone, and look up the note name.
semitones from A4 = 12 × log₂(freq / 440)
MIDI note = round(semitones) + 69
cents deviation = 1200 × log₂(freq / nearest_note_freq)
Note Frequency Reference Table
| Note | Hz | MIDI |
|---|---|---|
| C4 (Middle C) | 261.63 | 60 |
| D4 | 293.66 | 62 |
| E4 | 329.63 | 64 |
| F4 | 349.23 | 65 |
| G4 | 392.00 | 67 |
| A4 (Concert A) | 440.00 | 69 |
| B4 | 493.88 | 71 |
| C5 | 523.25 | 72 |
| A3 | 220.00 | 57 |
| A5 | 880.00 | 81 |
What Are Cents?
Cents are a logarithmic unit for measuring intervals between pitches. One semitone = 100 cents. A perfectly in-tune note has 0 cents deviation. Most human ears can detect deviations of about 5–10 cents. ±50 cents is the maximum deviation before a note is considered the next semitone.
- 0 cents — perfectly in tune
- ±5 cents — barely perceptible to most ears
- ±10 cents — most listeners notice slight out-of-tuneness
- ±25 cents — clearly out of tune
- ±50 cents — exactly between two notes
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