What is Line Height in Web Design?

Line-height is the amount of space between lines of text within a paragraph. For increased readability, it should be at least 150% of the text size or 1.5em. Example: 12px text should have at least 18px line-height or 1.5 em. When in doubt, you can always use the golden ratio (1.61em) as a rule of thumb. 

Line-height is used to create distance between lines of text. A best practice is to make line-height 150% of the text size.