CMYK ↔ RGB ↔ HEX Color Converter
About Line Height Calculator
The Optimal Line Height (Leading) & Vertical Rhythm Calculator evaluates font sizes, line character lengths (CPL), and font x-heights to calculate ideal, accessible unitless `line-height` values (1.2 to 1.7) conforming to WCAG 2.1 Success Criterion 1.4.12.
How to Use Line Height Calculator
Step 1
Enter font size in pixels and select text role (Heading, Body Text, or Caption).
Step 2
Review computed unitless `line-height` and pixel line distance.
Step 3
Inspect the live rendered prose paragraph preview.
Step 4
Click "Copy CSS".
Practical Use Cases for Line Height Calculator
Optimizing Reading Ergonomics & WCAG 2.1 Compliance
Calculate optimal line height for long-form prose (recommended: 1.5 to 1.65) to satisfy WCAG 1.4.12 text spacing accessibility standards.
Calculating Tight Heading Line Heights
Compute proportionate tight line-heights (1.1 to 1.25) for large display headlines to prevent awkward vertical gaps between wrapped lines.
Input & Output Examples
Calculating Line Height for 18px Body Text
Font Size: `18px`, Line Width: `65ch` (Optimal measure)
Unitless: `1.55` | Pixel Equivalent: `27.9px` | CSS: `font-size: 18px; line-height: 1.55;`
Key Features & Performance
- ✓Calculates: Unitless `line-height` (recommended), Pixel equivalent (`px`), and Percentage (`%`).
- ✓Considers line measure (Characters Per Line / Measure) for reading comfort.
- ✓WCAG 2.1 1.4.12 spacing validator: verifies line spacing meets 1.5x font size baseline for body text.
- ✓100% Client-Side memory execution.
- ✓1-Click Copy CSS declaration.
Key Terminology & Definitions
Unitless `line-height`
Declaring `line-height: 1.5` without units so child elements inherit the proportional multiplier rather than a fixed pixel height.
WCAG 2.1 SC 1.4.12 (Text Spacing)
An accessibility standard requiring line height to be at least 1.5 times the font size for body paragraph text.