Notation
If the note to be dotted is on a space, the dot also goes on the space, while if the note is on a line, the dot goes on the space above (this also goes for notes on ledger lines). However, if a dotted note on a line is part of a chord where a higher note is also on a line, the dot for the lower note is placed in the space below:
The dots on dotted notes, which are located to the right of the note, are not to be confused with the dots which indicate staccato articulation, which are located above or below the note as shown in the 3rd and 4th notes of Example 2.
Theoretically, any note value can be dotted, as can rests of any value. If the rest is in its normal position, dots are always placed in third staff space from the bottom.
The use of a dot for augmentation of a note dates back at least to the 10th century, although the exact amount of augmentation is disputed; see Neume.
Dots can be used across barlines, such as in H. C. Robbins Landon's edition of Joseph Haydn's Symphony No. 70 in D major, but most writers today regard this usage as obsolete and recommend using a tie across the barline instead.
More than one dot may be added; each dot adds half of the duration added by the previous dot, as shown in example 1.
Read more about this topic: Dotted Note