Hz to Note Converter
Use this Hz to note converter to find the nearest musical note for any frequency in Hertz — with cent deviation from equal temperament, MIDI number, and octave. Visual single-octave piano, side-by-side audio comparison, and adjustable A4 reference tuning (380–480 Hz).
Input
Nearest Note
Cents Deviation — Musical Perception Guide
| Cents off | Frequency ratio | Musical perception | Examples |
|---|---|---|---|
| 0 – 1 ¢ | 1.0000 – 1.00058 | Perfect — indistinguishable | Studio reference; lab instruments |
| 1 – 5 ¢ | 1.0006 – 1.0029 | Imperceptible to untrained ears | Well-tuned instruments |
| 5 – 15 ¢ | 1.0029 – 1.0087 | Audible to trained musicians | Slightly out of tune piano |
| 15 – 30 ¢ | 1.0087 – 1.0175 | Audible to most listeners | Cheap consumer tuning |
| 30 – 50 ¢ | 1.0175 – 1.0293 | Clearly out of tune | Approaches a quarter-tone |
| 50 – 100 ¢ | 1.0293 – 1.0595 | Almost a different note | Approaching the next semitone |
| 100 ¢ (exactly) | 1.0595 (12√2) | One whole semitone away | Definitely a different note |
About Cents, Notes & Tuning
Every musical note in 12-tone equal temperament has an exact frequency. When you measure a real-world frequency (from a tuning fork, an instrument, a recording, or a sound generator), it rarely lands precisely on a note — it's usually slightly sharp (above) or flat (below). The cents value tells you how far off you are. As a tuning calculator, this converter also functions as a quick pitch finder: type any Hz value and it immediately names the closest note, making it useful for identifying an unknown tone from a recording or a real instrument.
How the cent works
A cent is 1/100th of an equal-tempered semitone. There are 1,200 cents in an octave. The formula is cents = 1200 × log₂(f / f_target). A positive value means the input frequency is sharp (higher than the target note); a negative value means flat. Trained musicians can typically detect deviations of 5–10 cents; untrained listeners notice 15–25 cents and above.
Why the A4 reference matters
Every note's frequency is calculated relative to A4. Change A4 from 440 to 432 Hz and every note shifts proportionally — Middle C goes from 261.63 to 256.87 Hz. If you measure a 261.63 Hz tone with A4 = 432 reference, you'll see it's now +32 cents sharp relative to that tuning system. This tool lets you switch the reference freely to test alternative tunings. To generate a precise reference pitch at any A4 setting, the online tone generator lets you produce a sine wave at any frequency for direct ear-training and comparison.
What can shift a note's measured frequency?
Microphone latency and aliasing, room reverb and resonance, the natural inharmonicity of strings (especially piano bass strings), vibrato in singing, temperature-driven tuning drift, and intentional pitch-bending in performance. A "perfect" reading in software doesn't always mean a perfect performance — context matters. Converting Hz to musical note values is also useful in MIDI production: knowing the frequency to MIDI mapping lets you cross-check a synthesiser's oscillator pitch against an intended note, and the MIDI number shown in the results grid makes that lookup instant. If you want to verify a specific pitch in real time, the chromatic tuner captures live microphone input and shows cents deviation continuously rather than requiring manual frequency entry.
Equal temperament vs. other tuning systems
This converter calculates note names using 12-tone equal temperament (12-TET), where each octave is divided into 12 equal semitones. Other historical systems — just intonation, meantone temperament, Pythagorean tuning, and Baroque unequal temperaments — place the same note names at slightly different frequencies. For example, pure-fifth Pythagorean tuning places D4 at approximately 293.33 Hz rather than the equal-tempered 293.66 Hz. When analyzing audio from period instruments or choral music tuned to a different system, the cents deviation shown here reflects the distance from equal temperament, not from the performer's intended pitch.