In typography, leading ( /ˈlɛdɪŋ/) refers to the distance between the baselines of successive lines of type.

By this definition, isn't it the same thing as line height?

But in the following examples in the same wikipedia page, it seems leading is extra space between lines, not line height. Otherwise, "no leading" should mean "no line height" which is obviously wrong. And 50%/100% leading seems to mean adding an extra inter-line spacing of 50%/100% natural line height.

Wikipedia is not the only source that holds contradictory content. Another website in the first search result page of "font leading" also gives contradictory graphical demonstrations.

And if you are an iOS developer, you may know that UIFont has a property called leading which returns line height. The fact that the property is now deprecated and replaced by a new property call lineHeight further shows how confusing this leading thing is.

I'm inclined to think leading as extra space added between lines. And here are two references that support this understanding:

  • A glossary of typographic terms

    leading (pronounced: ledding) The amount of space added between lines of text to make the document legible. The term originally referred to the thin lead spacers that printers used to physically increase space between lines of metal type. Most applications automatically apply standard leading based on the point size of the font. Closer leading fits more text on the page, but decreases legibility. Looser leading spreads text out to fill a page and makes the document easier to read. Leading can also be negative, in which case the lines of text are so close that they overlap or touch.

  • CTParagraphStyle Reference

    kCTParagraphStyleSpecifierLineSpacing The space in points added between lines within the paragraph (commonly known as leading). This value is always nonnegative. Type: CGFloat. Default: 0.0. Application: CTFramesetter.

Maybe leading is really misleading. I hope someone can tell me definitely what exactly leading is. But maybe leading is just a typographic term that can never receive a consensus, thus should be avoided as much as possible, and even be deprecated in preference for more clear and compatible concepts such as ascent, descent, line gap, and line height(line height = ascent + descent + line gap).


4 Answers 4


The easiest way to understand the meaning of leading is to get a piece of paper and draw two lines. On these two lines, write some text. the distance between these two lines is the leading.

enter image description here

When typesetting the only "constant" parameter for laying out text is the baseline. Descenders, diagritics and subscripts can extend below this line. That is why normally everything relates to the baseline and not the bounding box of the letters.

For a good article and leading definition "woos" see http://www.creativepro.com/article/just-say-no-automatic-leading and of course Knuth did not help much in calling it "baselineskip".


I think the comment on the wikipedia page tells it all: "The word comes from lead strips that were put between set lines". That means the extra line height that are put between the letters. If you have a 10 pt font, the baselines would be 10 pt apart, but with extra leading (for example 2pt), they would be 12 pt apart. This is denoted as 10pt/12pt font size.

  • But how do you read "the distance between the baselines of successive lines"?
    – an0
    Jun 16, 2011 at 19:30
  • 7
    I think this is a somewhat pedantic version of the definition. Although it's technically correct to call the leading the extra space, in practice, the word is likely most often used to mean the distance between baselines.
    – Alan Munn
    Jun 16, 2011 at 19:37
  • 1
    @Alan That's where the confusion comes from: distance between baseline of line 1 and baseline of line 2 is(or is equal to) the height taken by line 2, isn't it? But in many other places(or maybe nearly all real life use cases), leading is used as the extra lining space which is added to ascender and descender to form the whole line height. Forgive me and correct me if I get it wrong - my mind is just boggled down.
    – an0
    Jun 16, 2011 at 20:53
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    @an0, I think the situation is opposite to what you describe. e.g. Graphic Design: Typography, Bringhurst notes, The Production Manual. (Some random web links on typography practice.)
    – Alan Munn
    Jun 16, 2011 at 21:06
  • 1
    @Alan and you should've noticed those articles you gave above even use wording such as "basic leading" and "additive leading" which makes thing even more confusing.
    – an0
    Jun 16, 2011 at 21:23

Really curious. Bringhurst says (The Elements of Typographic Style, v3.2, pp36-37) (my emphasis):¶4 ... This unit is the leading, which is the distance from one baseline to the next. ...

¶5 Add 2 points of lead (interlinear space), and the type is set 11/13

So his intent for the meaning is clear: (leading) = (typeface height+depth) + (lead), and he avoids the sloppy "line height", which could mean almost anything. But then, alas!, he trips over himself:

¶7 this is an example of negative leading

where for consistency, I think, he should have written

¶7 this is an example of negative lead

If the giants can get confused, then, is there hope for mere mortals like us?


There are really two conflicting terms at work here: leading, and the measurement of leading. In the former case, it refers to the actual strips of lead placed between lines of lead type, the height of which affects the vertical distance from the descenders of the preceding line to the ascenders of the following.

Leading measurement, on the other hand, refers to the distance between the baselines as affected by the amount of leading added. As Patrick's answer mentions, 10pt type with 2pt of leading has a leading measurement of 12pt.

With the advent of digital typesetting, leading measurement has come to be known as line height (e.g., the CSS line-height property), which is a rather more intuitive term to use considering that no typesetting software models its computations in terms of lead.

Although, come to think of it, perhaps it should.

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