A Typography Audit Reads Your Text at 400%

What We Keep Finding

Low-vision users read your site at 200%, 300%, 400% zoom, and the standard requires it to survive. Here is the number that makes that testable, because without it two testers get two answers. Zooming a 1280-pixel-wide window to 400% leaves you looking at the equivalent of a 320-pixel-wide viewport, and 320 is the width the rule actually names. So testing at 400% means testing at 320.

What the rule asks for at that width is no scrolling in two directions to read a line, and that is not the same as a single column, whatever you have been told. Content can stay in more than one column as long as nothing needs sideways scrolling to read. And there is an explicit list of things allowed to scroll both ways because they need it, so maps, diagrams, video, games, presentations and data tables are not reflow failures. That list is the answer to the first objection any reflow finding gets, and it is why we check it before we write one.

Spacing is the other override, and it is a survival test rather than a design instruction. You do not have to set your line height to one and a half times your font size. What you have to do is not break when a reader sets it themselves. That means double spacing after paragraphs, letter spacing at 0.12 times, and word spacing at 0.16 times, which is the one most tables leave out. Apply all four, then go looking for clipped descenders and text escaping fixed-height boxes.

Then the quiet one, text baked into a picture. It does not reflow, it does not recolor, and alt text does not fix it, because alt text satisfies a different rule than the one about images of text. That rule wants real text on the page. Logos are exempt, and the part people miss is that a logo is exempt from the contrast requirement too, so nobody should be raising a finding against your wordmark.

One last thing that saves an argument. Zooming does not turn your body text into large text. The rule's own definition fixes font size at the size the content was delivered at, so the friendlier 3:1 contrast allowance for large text never arrives just because somebody zoomed in. And on the flip side, setting your font sizes in pixels is not itself a failure of anything. There is a documented failure for viewport units and none for pixels, so if a report told you to convert your whole stylesheet, ask which rule.