In 4/4 a dotted half note is 3 beats, a dotted quarter 1½ and a dotted eighth ¾. The dot adds half of the note’s own value, not a fixed half beat.
A dot multiplies by 1.5; it does not add half a beat. The difference shows up immediately on a dotted eighth: 0.5 × 1.5 = 0.75 beats, not 1. Anyone carrying "add half a beat" in their head miscounts the first dotted-eighth rhythm they meet.
Dotted quarter plus eighth makes two beats — much the most common dotted figure.
Written
By itself
The dot adds
Total
Dotted half note
2 beats
+1
3 beats
Dotted quarter note
1 beat
+½
1½ beats
Dotted eighth note
½ beat
+¼
¾ beat
A dotted quarter is nearly always followed by an eighth, and the pair fills two beats. The feel is long–short, with the short note pressed right up against the next beat. Count it "one, two AND" and play the eighth on the "and".
Common questions
How many beats is a dotted half note?
Three beats when the quarter note is the beat: the half note’s two plus one for the dot. In 3/4 a dotted half note fills the entire measure.
How long is a dotted quarter note?
One and a half beats: one for the quarter note and half a beat for the dot. In 4/4 it is usually followed by an eighth note, and the pair adds up to two beats.
What does a double dot mean?
The second dot adds half of what the first dot added, so the note lasts 1¾ times its plain length. A double-dotted half note is 3½ beats.