Leading

Leading is the baseline-to-baseline vertical rhythm between lines of text. It determines density, readability, and visual order before the reader decodes a single word. CSS calls it line-height yet that label misleads teams into treating it like a box dimension instead of a structural spine. In any real typographic hierarchy leading works as the silent lever that size and weight depend on. Tight leading on headlines stacks letters into confident dense blocks that signal immediate importance. Looser leading on body text opens the rhythm so the eye travels smoothly across paragraphs. The article on typographic hierarchy calls this the most undervalued control because designers obsess over font choice and size ratios then apply one lazy multiplier everywhere and wonder why the page feels flat. Bigger type needs less leading. Smaller type needs more. A 72px H1 at 1.6 feels like decoration while a 16px body at 1.2 feels like a concrete wall. These choices either reinforce the five-level system or destroy it.

Leading is not the margin between a heading and its following paragraph. That belongs to section spacing and vertical rhythm. It is not tracking which spreads letters horizontally and only earns its keep on display sizes or small uppercase labels. It is not a universal 1.5 value applied from H1 down to captions. Teams that do this invert the hierarchy and flatten contrast regardless of their perfect fourth scale. It is not an eyeball adjustment made at the end of a Figma file or a per-page tweak left for developers to improvise. It is not best expressed in fixed pixels that break when users increase their browser font size. Leading decisions belong in the first round of system building right after base size and scale ratio are locked. Anything else produces the broken patterns the hierarchy article warns against.

Concrete example. Linear's 2024 interface refresh used a perfect fourth scale from a 16px base. Their H1 token at 42px deploys 1.1 leading which makes command bars and issue titles feel fast and authoritative. Body text at 16px runs 1.65 leading so long descriptions in task views stay scannable during marathon work sessions without fatigue. Small metadata at 13px uses 1.45 leading. The contrast across these three values does more work than weight or color. The same team ships their public marketing site with the identical typeface yet opens body leading to 1.72 because readers there consume longer editorial content. One system two contexts precise leading per role. Another example lives in The Verge redesign delivered in early 2025. Their article pages tightened body leading from the previous 1.85 to 1.57 on 17px text. Scan time dropped measurably while readers reported less eye strain on long features. Headlines at 32px sit at 1.15 which creates a visible step down in rhythm that tells the eye where the section break ends and the story begins. The failure contrast appears in countless 2022-2023 SaaS landing pages that copied a popular Webflow template. Those heroes set 56px headlines at 1.58 leading. The type looked weightless and conversions suffered until teams clamped the value to 1.12. Nothing else in the layout changed. The silent lever carried the difference.

Use tight leading on every headline and display level. Lock H1 and H2 between 1.1 and 1.2. Allow H3 to open to 1.3 at most. This range creates the dense texture that makes headings read as structure not decoration and it scales correctly across dashboards marketing sites and documentation. Use looser leading for body text with the 1.5 to 1.7 range as your default. Long-form editorial like Brainy Papers articles needs the higher end while dense admin tools such as Stripe Billing or Vercel dashboards can tighten to 1.4 because their text blocks stay short. Captions and form labels sit at 1.4 to 1.5 because their smaller size requires extra air to remain legible at 13px. Always validate these values against real content on three screens: homepage hero long-form article and settings panel. If the rhythm survives all three ship it.

Never use loose leading on large type. The 2022 hero-text epidemic of 1.6 multipliers turned marketing sites into floaty balloons that users scrolled past. Never tighten body text below 1.45 on 16px or larger. The resulting slabs increase bounce rates and fail every accessibility check that matters in 2026. Never apply identical leading to adjacent hierarchy levels. That kills contrast as effectively as using the same weight. Never design leading only at desktop sizes then pray it works at 375px. Mobile compresses everything and turns loose desktop values into wasteful vertical scroll. Never set leading last after sizes and weights are chosen. Follow the exact decision order in the parent article: base size scale ratio weights leading then 2-to-1 spacing. Reverse it and you will spend the next quarter patching pages instead of shipping product.

Leading done right disappears so the reader experiences only clarity and momentum.