Piano Tuning Calculator

Target Frequency follows an exponential equal-temperament curve across the full 88-key range, so moving Key Number by even a few positions shifts the frequency by a larger amount than a proportional change to Reference A4 Frequency does. Reference A4 Frequency scales every note by the same ratio, but Key Number determines which note -- and therefore which frequency band -- you're targeting in the first place.

Some orchestras and recording contexts use 442 Hz or occasionally 415 Hz for historical (baroque) tuning. Raising Reference A4 Frequency raises the target frequency of every note by the same proportional amount, so the whole piano shifts together rather than changing pitch relationships between notes.

Piano strings are stiff rods, not the ideal flexible strings equal-temperament math assumes, so their overtones run slightly sharp of a pure harmonic series -- an effect called inharmonicity. Stretching the tuning (sharpening high notes, flattening low notes relative to pure equal temperament) makes the piano's own overtones line up better with each other than a mathematically pure tuning would, which is why real pianos sound more in tune when deliberately mistuned from theory.

No -- it applies one simplified stretch curve based only on distance from A4, while real tuning devices and technicians measure each individual piano's actual inharmonicity coefficients, which vary by string gauge, scale design, and age. Use this for a reference starting point or to understand the concept, not as the target values for a production tuning job.

Frequency Deviation from Equal Temp is Cents from Equal Temp converted into Hz -- how far this specific note's stretched/tempered pitch has drifted from a theoretically pure equal-tempered reference. It is not the audible "beating" a tuner hears between two notes sounding together (like a slightly-off fifth), even though tuners often use "beat" for that different, two-note phenomenon. Tuning Order Priority is simply each key's distance from key 42 (near the center of the keyboard), reflecting the common practice of tuning the center octave first -- where pitches are easiest to hear accurately -- and working outward from there.