# Cents

Source: https://arcosounds.com/glossary/cents

**A cent is a unit of pitch measurement equal to one hundredth of an equal-tempered half step, used by tuners to show how far a note is from true.**

Twelve hundred cents make an octave. The threshold where a typical listener perceives a note as out of tune sits around five to ten cents in a sustained context, though beating between two simultaneous notes reveals much smaller discrepancies, which is why double stops are a more sensitive intonation test than single notes.

Cents also explain why tuning systems differ. A pure major third is about fourteen cents narrower than the equal-tempered one, which is why string quartets playing by ear drift away from piano tuning, and why a chord can be locked in tune with itself while every note reads slightly off on a tuner.

Canonical source: https://arcosounds.com/glossary/cents