What is the right line spacing for web?

Line spacing is the amount of space between lines of text within a paragraph. For increased readability, it should be at least a 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 too.

 
line-height.jpg