Note to Frequency Calculator

About this calculator

In equal temperament — the tuning system used by virtually all modern Western instruments — each semitone is a fixed frequency ratio of the 12th root of 2 (≈1.05946) apart. This calculator finds a note's frequency with f = A4 × 2^((n − 49)/12), where n is the note's position on a standard 88-key piano and A4 is the reference pitch, adjustable from the concert standard of 440 Hz to alternate tunings like 442 Hz used by some European orchestras.

Musicians tuning instruments by ear or electronic tuner, audio engineers designing synthesizers, and piano technicians rely on this note-to-hertz relationship daily — it's the same math behind every digital tuner and synth oscillator. Because equal temperament slightly compromises the “pure” harmonic ratios found in just intonation, the calculator is also a useful reference for anyone studying the difference between the two tuning systems.