Paragraph spacing must exceed leading or the break cannot be seen

What it is

A paragraph is a group of lines. People carve that group from the next one by “tighter inside, looser between.” If the space between paragraphs equals the space between lines, the grouping signal is zero and the page is an even field of lines. Paragraph spacing versus leading is a threshold for the break cue, not the empty claim that “paragraphs should have space.”

Why it happens

Proximity ranks by distance: nearer elements are grouped. Inside a paragraph the baseline-to-baseline distance is leading; between paragraphs an extra gap is added. Readers compare those two quantities. When paragraph spacing is less than or equal to leading, the comparison says “everything is equally near,” and the boundary vanishes from space, leaving only periods and indents (if any) to do the work. A common screen failure is to give paragraph spacing and leading the same token: tidy, and no grouping occurs. Once the gap exceeds leading, the surplus is the break signal. Far too much surplus and paragraphs drift apart like unrelated cards — overcompensation, not the aim here.

Where it stops holding

A one-line paragraph barely has internal leading, so paragraph spacing behaves like item spacing and the comparison target changes. Lists and chat bubbles use item gaps, not paragraph gaps; do not hold them to leading. When a first-line indent is the primary cue, paragraph spacing may equal leading or even drop to zero — the cue has moved to the horizontal. Vertical Chinese compares column gap to inter-paragraph space; the axis rotates ninety degrees, the inequality still holds.

Applying it

• Measure two adjacent body paragraphs: height of a line box, size of the gap between blocks. The latter must be obviously larger, separable by eye, not one or two pixels on a ruler.
• Cover paragraph marks and indents, leave only spacing, and ask whether the break is still pointable. If it is not, spacing has not yet cleared leading.
• Do not use “one blank line” as a spoken unit — a blank line equal to leading is still a zero signal. Speak in multiples: paragraph spacing around one and a half to two times leading, then tighten for density.

Related

• Same group: F4.13.2 First-line indent and a blank between paragraphs are mutually exclusive conventions · F4.13.3 A long unsegmented block drops reading completion · F4.13.4 Paragraph spacing should track leading, not a fixed pixel value
• Nearby: F4.02 Leading · F2.06 Grouping by proximity
• Search terms: paragraph spacing · leading · proximity