Cap height is the height of a [typeface](/glossary/typeface)’s [uppercase](/glossary/uppercase_lowercase) letters, measured from the [baseline](/glossary/baseline) to the top of flat-topped [glyphs](/glossary/glyph). This is usually slightly lower than the ascender height, and cap height can vary between typefaces.

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![The word “Newsreading” set in a serif typeface, with horizontal lines showing the vertical metrics. The cap height line is highlighted, and an arrow shows the measurement from baseline to cap height.](images/thumbnail.svg)

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Note that due to optical illusion, round and pointed capitals (for instance the O and A) will extend a little above the cap height to make them appear as tall as the flat-topped capitals.