Musical Note Frequency Reference

Note Frequencies by Octave

Equal temperament frequencies at A=440 Hz. Click any note to see all temperament variants.

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Concert Pitch Variants

Concert pitch varies by orchestra and era. A=440 Hz is the ISO 16:1975 standard used by most modern ensembles. European orchestras often tune to A=442 Hz for a brighter sound. Baroque performers use A=415 Hz, approximately a semitone lower, to match the pitch of historical instruments. Some musicians prefer A=432 Hz, while other orchestras use A=443 Hz.

See all concert pitch reference pages: A=440 | A=442 | A=432 | A=415 | A=443

Why Frequencies Differ Across Tuning Systems

In equal temperament, the octave is divided into 12 mathematically equal semitones, making every key sound identical but with slightly impure intervals. In Pythagorean tuning, fifths are pure (3:2 ratio), but the octave closure creates the Pythagorean comma of approximately 23.46 cents. Just intonation uses integer ratios for maximum consonance in thirds and fifths, but limits playable keys.

Historical well-temperaments such as Werckmeister III, Kirnberger III, and Vallotti distribute these acoustic trade-offs across all keys so that every key is usable while preserving distinct tonal colors. Meantone temperaments prioritize pure major thirds at the expense of some fifths. Each note page on this site shows how these systems produce different frequencies for the same pitch, with cent deviations from equal temperament.