WCAG AAA Text Size
Recommends minimum text size in pixels for WCAG AAA at typical reading distance.
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WCAG AAA recommended text size
At the AAA level, WCAG 2.1 pushes the contrast ratio up to 7:1 for normal text. Large text (≥ 18pt regular or ≥ 14pt bold) gets a bit of slack at 4.5:1. To pick a font size, the practical rule is to scale with how far away the reader sits: size_pt ≈ distance_cm / 2.5. That keeps text readable for people with low vision.
A few related criteria matter here. Success Criterion 1.4.10 Reflow says content has to fit a 320 CSS pixel viewport without forcing horizontal scroll. 1.4.4 Resize Text wants text to enlarge up to 200% with nothing lost along the way. And SC 1.4.5 / 1.4.9 steers you away from text baked into images, logotypes being the one exception.
Applications
Think government portals, banking apps, healthcare dashboards, or anything chasing AAA conformance. It matters most when your audience includes older adults or low-vision users, or when the viewing distance keeps changing (TVs, kiosks, in-car displays). To check your work, lean on axe DevTools, Lighthouse, WAVE, and Pa11y.
FAQ
What is the minimum body text size on the web? WCAG never nails down a pixel number. In practice 16px (12pt) is where most people start, and designs aiming at AAA tend to push body copy to 18–20px.
Does zooming the browser satisfy 1.4.4? It can. As long as the layout, the controls, and the content all stay usable at 200% zoom with no horizontal scroll on a 1280px viewport, you've met the criterion.
How is contrast measured? It comes from the WCAG luminance formula (L1 + 0.05) / (L2 + 0.05), where L1 and L2 are the relative luminances of the foreground and the background.
Related Tools
WCAG AA Text Size
Recommends a minimum body text size in pixels for WCAG AA at typical reading distance.
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Compute minimum font size for WCAG 2.1 accessibility: AA (16px body, 24px heading), AAA (18.66px body, 36px heading). Configurable.
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Checks if a touch target meets the WCAG 2.5.5 minimum of 44x44 CSS pixels.
Cohen's h (Effect Size for Proportions)
Computes Cohen's h, the effect-size measure for the difference between two proportions. Comparing proportions directly is misleading, because the same arithmetic difference weighs differently near the middle (0.5) and near the ends (0 or 1). Cohen's h fixes this by applying the arcsine transformation, which stabilizes the variance, before measuring the distance. Usual convention: 0.2 is small, 0.5 medium and 0.8 large. Enter the two proportions (between 0 and 1).
Garage Gate Vehicle Size Calculator
Computes minimum garage gate width and height based on vehicle type and recommended side clearance for passenger cars and pickup trucks.
Recommended Weight Limit (NIOSH)
Computes the recommended weight limit from the 1991 revised NIOSH lifting equation, RWL = 23 kg × (25 ÷ H, with H floored at 25) × (1 − 0.003 × |V − 75|) × (0.82 + 4.5 ÷ D) × (1 − 0.0032 × A) × FM × CM, where H is the horizontal distance in centimetres between the hands and the midpoint of the ankles, V is the hand height at the start of the lift, D is the vertical travel of the load and A is the asymmetry angle in degrees. The 23 kg is the load constant, the maximum acceptable under ideal conditions — load against the body, at knuckle height, no trunk twist and lifted infrequently — and each multiplier discounts a fraction as the task departs from that condition. FM, the frequency multiplier, and CM, the coupling multiplier, come from the standard's own tables and therefore enter as data rather than calculation: FM depends on lifts per minute, shift duration and height range; CM on grip quality, rated good, fair or poor. Divide the weight actually lifted by the RWL to get the lifting index: above 1 the task already exposes part of the population to low back risk, and above 3 the risk is high for nearly everyone. Both H and D are floored at 25 cm by the standard itself, so below that the multiplier locks at 1 with no warning on screen: typing the distance in metres instead of centimetres passes validation and returns a limit that is too permissive. Enter the horizontal distance, the starting hand height, the vertical travel, the asymmetry angle, the frequency multiplier and the coupling multiplier.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.