AudioCalcs
Frequency to Note Calculator — Find the Nearest Musical Note
Find the closest musical note to any frequency, with cents deviation and MIDI note number.
How We Calculate This
The calculator uses the equal temperament formula to find the nearest note, where A4ref is the Reference A4 you set (default 440 Hz):
Semitones from A4 = 12 × log2(f / A4ref)
The result is rounded to the nearest integer to find the closest note. The fractional part, multiplied by 100, gives the cents deviation.
Exact frequency of note = A4ref × 2^(n/12)
where n is the number of semitones from A4. Setting Reference A4 to 432 or 442 Hz shifts every note frequency accordingly.
Frequently Asked Questions
A cent is 1/100th of a semitone. There are 1200 cents in an octave. Cents are used to express small deviations from equal temperament tuning. Most people cannot perceive a difference of less than 5-10 cents.
A4 = 440 Hz was recommended internationally in 1939 and adopted by the ISO as Recommendation R 16 in 1955, then formalised as the standard ISO 16:1975. Before standardisation, concert pitch varied widely. Some orchestras still tune to A4 = 442 or 443 Hz for a brighter sound.
MIDI note numbers range from 0 to 127, where 60 is middle C (C4) and 69 is A4 (440 Hz). Each increment represents one semitone. MIDI note numbers are used in digital audio workstations and synthesisers.
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Last updated: February 2026
All calculations are estimates based on standard formulas. Always verify results for critical applications.