Note Frequency Calculator

The standard frequency of A4 is 440 Hz, established as the international pitch standard in 1955. However, some musicians prefer 432 Hz (often called 'Verdi pitch') or 442 Hz (commonly used in European orchestras). Our calculator lets you adjust this reference to any value between 415-466 Hz.

Note frequencies are calculated using the equal temperament formula: f = A4 × 2^(n/12), where n is the number of semitones from A4. This formula ensures that each semitone has an equal frequency ratio of approximately 1.059463 (the 12th root of 2).

440 Hz is the modern international standard. 432 Hz is an alternative tuning that some believe sounds more natural or harmonious. All note frequencies shift proportionally when you change the A4 reference - for example, with 432 Hz tuning, C4 becomes approximately 256.87 Hz instead of 261.63 Hz.

MIDI note numbers are integers from 0 to 127 that represent musical pitches. Middle C (C4) is MIDI note 60, and A4 (440 Hz) is MIDI note 69. Each semitone increases the MIDI number by 1. This standardized numbering system allows digital instruments and software to communicate pitch information.

Wavelength affects how sound interacts with physical spaces. Low frequencies have long wavelengths (bass notes can be several meters), while high frequencies have short wavelengths. This is important for room acoustics, speaker design, and understanding sound propagation. The wavelength is calculated as: λ = speed of sound / frequency.

Humans can typically hear frequencies between 20 Hz and 20,000 Hz. Musical instruments generally produce fundamental frequencies from about 27.5 Hz (A0 on a piano) to about 4,186 Hz (C8). However, instruments also produce harmonics that extend well above these fundamental frequencies.