Start with 100 cents: one semitone
Two neighboring piano keys are usually one semitone apart, or 100 cents. A 20-cent deviation is not one note away; it is one fifth of a semitone.
Cents measure distance between pitches. In 12-tone equal temperament, one semitone is 100 cents and one octave is 1200 cents. For singers, cents deviation shows whether you are sharp, flat, or falling at the end.
If a pitch monitor shows +20 cents, you are about one fifth of a semitone sharp; -20 cents means flat. In practice, do not chase a single zero reading. Aim for a 3 to 5 second curve that stays stably around the target.
Two neighboring piano keys are usually one semitone apart, or 100 cents. A 20-cent deviation is not one note away; it is one fifth of a semitone.
A positive value means sharp; a negative value means flat. First identify the direction, then the size, so you know whether to nudge up or ease down.
Sung pitch naturally moves. A better check is whether the curve stays around the target for 3 to 5 seconds, not whether one frame happens to show 0.
Play a comfortable reference note with Piano, listen clearly, then sing instead of guessing from memory.
Hold a 3 to 5 second note and note whether it is mostly + or -, and whether the deviation grows.
Use ear training and echo drills to turn visible deviation into audible difference.
There is no single hard line for every musical context. For self-practice, watch direction and stability first: if you are consistently + or -, or endings keep falling, isolate and fix it.
A voice is not an electronic keyboard. Attacks, vibrato, breath, and vowels all move the fundamental frequency. A short trend is more reliable than one instant number.