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About WCAG Text Size Calculator
The WCAG 2.1 / 2.2 Text Size & Visual Accessibility Threshold Calculator classifies typography as "Large Text" vs. "Normal Text" according to W3C guidelines, calculating required minimum contrast ratios (3:1 vs. 4.5:1) in `px`, `pt`, `rem`, and `em`.
How to Use WCAG Text Size Calculator
Step 1
Enter font size in `px`, `pt`, or `rem`.
Step 2
Select font weight (Normal 400 or Bold 700+).
Step 3
Review computed WCAG text classification and required contrast ratio threshold.
Step 4
Click "Copy Accessibility Matrix".
Practical Use Cases for WCAG Text Size Calculator
Design System Typography & WCAG AA / AAA Compliance Verification
Determine whether UI heading and body text scales qualify for reduced 3:1 contrast ratios under WCAG Level AA Large Text rules.
Responsive CSS rem/px Conversion for Accessible Heading Hierarchy
Verify that mobile typography scaled in `rem` units maintains WCAG large text thresholds across desktop and mobile viewports.
Input & Output Examples
Evaluating 14pt Bold Heading (18.66px Bold)
Font Size: `18.66px (14pt)`, Font Weight: `Bold (700)`
Classification: `WCAG Large Text` | Minimum Contrast: `3.0:1 (AA)` / `4.5:1 (AAA)` | Status: `Eligible for 3:1 Contrast Exemption`
Key Features & Performance
- ✓WCAG Definition Engine: applies official W3C definitions (18pt / 24px regular or 14pt / 18.66px bold).
- ✓Multi-Unit Converter: converts effortlessly between `px`, `pt`, `rem`, `em`, and `%` based on root font size.
- ✓Level AA vs. Level AAA Matrix: displays exact contrast requirements for normal text ($4.5:1 / 7:1$) and large text ($3:1 / 4.5:1$).
- ✓100% Client-Side memory execution.
- ✓1-Click Copy CSS typography specs.
Key Terminology & Definitions
WCAG Large Text
Text defined by W3C as being at least 18pt (24px) in regular weight or at least 14pt (18.66px) in bold weight, requiring lower contrast ratios (3:1 AA).
Points (pt) to Pixels (px) Conversion
Under standard CSS specifications, $1\text{ pt} = 1/72\text{ inch} = 1.333\text{ px}$ ($18\text{ pt} = 24\text{ px}$, $14\text{ pt} = 18.66\text{ px}$).