Note Frequency Calculator
Frequency in Hz for any musical note, with adjustable concert pitch.
Overview
The note frequency calculator returns the exact frequency in Hertz for any musical note across the audible range, with a configurable concert pitch reference (A4 = 440 by default, but adjustable to 442, 415, or any value). Type in a note name like A4, F#5, or Bb2 and the tool gives you the precise Hz.
It's a daily tool for synth designers tuning oscillators, instrument builders cutting strings or pipes to the right length, audio engineers identifying frequencies that ring or feedback during a mix, and orchestral musicians comparing pitches against a chromatic tuner reference. Knowing the underlying numbers helps you reason about EQ choices, room modes, and harmonic stacking precisely.
How it works
In 12-tone equal temperament, each note's frequency is calculated from a reference. Starting from A4 = 440 Hz, every semitone up multiplies the frequency by 2^(1/12) (about 1.0595), and every semitone down divides by the same ratio. So A#4 = 466.16 Hz, B4 = 493.88 Hz, and going down, G#4 = 415.30 Hz. Going up an octave doubles the frequency exactly (A5 = 880 Hz, A6 = 1760 Hz).
Concert pitch is configurable because not every ensemble uses A=440. Baroque ensembles tune to A=415 (a semitone lower) to match historical instruments. Many European orchestras tune slightly sharp at A=442 or 444 for added brightness. Shifting the reference rescales every note in the chromatic scale by the same ratio, so the relationships between notes stay constant.
Examples
A4 @ 440 Hz reference → 440.00 Hz
Middle C (C4) → 261.63 Hz
Low E on bass guitar (E1) → 41.20 Hz
A4 @ 442 Hz reference → 442.00 Hz (every other note shifted +7.85 cents)
FAQ
Why is middle C labelled C4?
It's the fourth C from the bottom of an 88-key piano. Different naming conventions exist (MIDI calls it C3 or C5 depending on the implementation), but scientific pitch notation labels it C4.
What's the lowest frequency a human ear can hear?
Roughly 20 Hz, which is between E0 (20.6 Hz) and F0. Most music stays well above this; subwoofers handle the lowest audible content.
How high do real instruments go?
The piccolo and violin harmonics reach above C8 (4186 Hz). Audible upper harmonics of any instrument extend much higher — up to 15-20 kHz for cymbals and bowed strings.
Why do bass notes sound "muddy" if you stack them?
Low-frequency intervals share more closely spaced harmonics, creating beats and intermodulation. Mixing engineers typically spread bass notes wider in time or keep them rooted around the fundamental.
Does string tension or pipe length change the formula?
Yes — physical instruments deviate slightly from pure equal temperament due to inharmonicity (especially piano strings, which sound slightly sharp in higher partials). The tool gives ideal mathematical pitches.