English: A comparison of various line spacings. The red lines are the line heights. In the true single line spacing the line height (L) is equal to the font height (h, the green line), in other words 100% or 1em. Important note. In many word processors (Microsoft Word, Open Office Writer), automatic leading is applied. That means the "single" line spacing is in fact 115% or 1.15em, so the "1.5" line spacing is 172.5% or 1.725em, the "double" line spacing is 230% or 2.3em.