Leading

Leading is the vertical space from one line of text to the next, the gap that decides whether a paragraph feels breathable or packed tight.

The name comes from strips of lead printers once placed between rows of metal type. The metal is gone, but the measurement stayed. On screens, developers usually call it line height. Leading and line height are two names for the same vertical decision.

Body text often feels comfortable when the line height is roughly 1.4 to 1.6 times the font size. Sixteen-pixel text at a 24-pixel line height is 1.5, right in the useful middle. Large headlines need less because their letters already create generous space, while small text needs more help.

Too tight and descenders from one line crowd the capitals below. Too loose and the lines stop reading as one paragraph. Kerning adjusts a specific pair of letters, and tracking spreads a whole word. Leading works in the other direction, between the rows.

The ratio is a starting point, not a law. Typeface, line length, and screen size all change what feels right. If your eye keeps losing the next line, adjust the leading before changing the words.