Understanding Leading

Leading is a typographical term referring to the vertical space from the same point on one line to the same point on the next, within the same paragraph. Typically, this distance is measured from baseline to baseline, where the baseline is the reference line on which your characters rest.

Leading is typically measured in points. In Word, leading is referred to as Line Spacing, although this is not technically correct. Line spacing is more comprehensive, implying less exacting terms or measurements than required by traditional typesetting.

When you want to specify your leading, you should follow an old typographical convention that states that line leading should be 120% of the point size of your font. Thus, according to this rule, if the font you are using is 10-point Arial, then your line leading should be 12 points. In typographical terms, this is referred to as 10/12 Arial (pronounced "10 on 12 Arial"). Likewise, if you are using 28-point Courier, then your leading should be 33.6 points. You can round this to 34 points, even though Word will accept fractional point sizes.

There are several methods Word can use for leading. Typically, the default leading type (as specified in the Line Spacing field of the Paragraph dialog box) is Auto. This means that line leading will be adjusted, automatically, based on the largest font size or element on each individual line. Word does this by applying the 120% rule to the largest font size or element on the line.

The problem with Auto leading is that it can leave your paragraphs looking uneven and choppy, particularly if you mix fonts and point sizes within the same paragraph. To overcome this, always specify that Line Spacing should be Exactly, and then set a point size in the At box.