Tuning Cents Deviation Calculator

Instrument tuning in cents: rule and example

To find how far a measured frequency sits from a reference, expressed in cents, use cents = 1200 · log₂(f_measured/f_ref). A semitone is exactly 100 cents, an octave is 1200. A well-trained ear catches deviations of 5-10 cents, while the average listener needs something closer to 10-15. Measure 441 Hz against the standard A4 = 440 Hz and you get about +3.93 cents, which means it sits a touch sharp of the reference. Tuners like the Korg TM-60 or Boss TU-3 usually show ±20 or ±50 cents on screen.

Applications

Guitarists lean on cents when setting bridge intonation, comparing the open string (say E2 at 82.41 Hz) against the 12th-fret harmonic. Violinists tune A4 = 440 Hz, though many European orchestras prefer 442 Hz. Piano technicians stretch the octaves following the Railsback curve, widening them 20-30 cents toward the extremes. Outside equal temperament, Arabic maqam relies on quarter-tones of roughly 50 cents, and Indian classical music divides the scale into 22 shrutis with intervals that don't land on neat 100-cent steps.

FAQ

Positive or negative cents? A positive number means you're sharp, above the reference. A negative one means you're flat, below it.

How many cents is "in tune"? On most instruments, landing within ±5 cents is excellent, and ±10-15 cents still passes when you're playing in a group.

Why use cents instead of Hz? Cents match how we actually hear pitch. 100 cents always sounds like a semitone, whereas 1 Hz is a huge gap at A2 and barely noticeable at A6.

Does temperature affect this? It does. Wind and string instruments climb about 5-10 cents as they warm up.