What Is the Line Height Calculator?
Calculate optimal line-height values for any font size. Preview text readability with adjustable font, size, and line-height combinations. Line height locks the vertical rhythm; the Optical Size Adjuster uses font-size-adjust to keep the rhythm intact during the fallback-to-web-font swap. For locking every element (headings, paragraphs, lists, margins) onto a single baseline grid rather than tuning each line-height individually, the Vertical Rhythm Calculator derives everything from one base unit. Once the rhythm is set, the Hyphenation Tester previews text-wrap pretty alongside hyphens auto to refine how lines break inside that rhythm.
Why Use This Tool?
Line height (leading) is one of the most impactful typography settings for readability. Too tight and lines blur together; too loose and the eye loses track between lines. This tool helps you find the sweet spot.
How to Use This Line Height Calculator
- Enter your font size — Type the font size you're working with in pixels. Common values: 14–16px for body text, 24–48px for headings.
- Choose a ratio — Select a line-height multiplier. The tool suggests optimal ratios based on your font size and content type (body text, headings, captions).
- Preview the result — See your text rendered live with the calculated line-height applied. Compare different ratios side by side.
- Copy the CSS — Grab the line-height value as a unitless ratio (recommended) or in pixels, rem, or em — ready for your stylesheet.
Tips and Best Practices
- → Use unitless line-height values. A unitless value like
line-height: 1.6scales proportionally with font size. Pixel or em values can cause unexpected results when font sizes change. - → Smaller fonts need more line-height. Body text (14–16px) reads best at 1.5–1.7 line-height. Large headings (32px+) can use tighter values like 1.1–1.3 because the letterforms are large enough to track without extra space.
- → Match line-height to line length. Longer lines need more line-height to help the eye return to the start of the next line. Short columns (like sidebars) can use tighter spacing.
- → Test with real content. Lorem ipsum doesn't reveal problems that real content does. Test your line-height with paragraphs that include ascenders (d, h, l) and descenders (g, p, y) to ensure nothing clips.
- → Set line-height on the body. Declare your base line-height on the
bodyelement and override it only for headings and special elements. This creates consistency throughout your design.
Frequently Asked Questions
Built by Derek Giordano · Part of Ultimate Design Tools