What is the minimum font size required by WCAG?

WCAG 2.1 does not mandate a specific minimum font size for compliance, but defines "large text" as ≥18pt (≈24px) at normal weight or ≥14pt (≈18.67px) at bold weight. Text meeting this threshold may use a lower contrast ratio of 3:1 instead of 4.5:1.

What is the difference between px and pt?

At the standard screen resolution of 96 DPI, 1pt = 1.333px. So 18pt ≈ 24px and 14pt ≈ 18.67px. Print and some design tools use 72 DPI where 1pt = 1px, which can cause confusion. This tool always uses the 96 DPI screen conversion.

What contrast ratio do I need for large text?

WCAG 2.1 Level AA requires a 3:1 contrast ratio for large text (≥18pt normal or ≥14pt bold). Level AAA requires 4.5:1. For normal text that does not meet the large text threshold, AA requires 4.5:1 and AAA requires 7:1.

Is 16px really the recommended body text minimum?

Yes. While WCAG does not enforce 16px, usability research consistently shows that body text below 16px (12pt) is harder to read for users with low vision or cognitive disabilities. Many accessibility experts and style guides recommend 16px as the body copy minimum.

Does em and rem scale affect WCAG classification?

Yes. If a user changes browser default font size, em/rem values scale accordingly and may cross the large text threshold. This tool calculates relative sizes assuming a 16px browser default, which is the standard assumption for static audit purposes.

Font Size Accessibility Checker

Name: Font Size Accessibility Checker
Availability: InStock
Author: Nham Vu

Enter a font size and weight to instantly see if it meets WCAG 2.1 AA and AAA readability requirements for body text and UI components.

Font Size

Assumes 96 DPI and 16px browser default for em/rem.

Font Weight

Size Conversions

Pixels (px): 16 px
Points (pt): 12 pt
Em / Rem: 1 em

Live Preview

The quick brown fox jumps over the lazy dog.

WCAG 2.1 Text Classification

Normal Text

Below the large text threshold.

Required Contrast Ratio

WCAG AA

Minimum compliance

4.5:1

WCAG AAA

Enhanced compliance

7:1

Readability Checks

WCAG Large Text Thresholds

Weight	Minimum pt	Minimum px
Normal (400)	18 pt	24 px
Bold (700+)	14 pt	18.67 px

Summary

Enter a font size and weight to instantly see if it meets WCAG 2.1 AA and AAA readability requirements for body text and UI components.

How it works

Enter your font size in pixels, points, em, or rem units.
Select the font weight (normal or bold).
The tool converts your value to both px and pt for comparison.
It checks WCAG 2.1 definitions: large text is ≥18pt normal or ≥14pt bold.
Pass/fail badges show which contrast ratio threshold (3:1 vs 4.5:1) applies.
A readability verdict flags sizes below 16px body text or 12px UI minimums.

Use cases

Verify that body copy meets the 16px minimum recommended for readability.
Confirm a heading qualifies as WCAG "large text" to relax contrast requirements.
Audit UI labels, captions, and helper text for accessible sizes.
Educate designers on the pt/px relationship and WCAG size thresholds.
Check mobile font sizes that may be scaled differently than desktop.
Quickly convert between px, pt, em, and rem during design reviews.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu