Character counter

A character counter only earns its place when a limit is real and tight enough to hit. Under a generous cap the count is noise, and readers learn to ignore it. The counter is also an admission: every one of them is a limit the system could not absorb quietly, so the first question is whether the field needs a maximum at all.

Two idioms exist and they say different things. “34/40” reports the state of the field, and “6 characters remaining” reports the budget left. The second reads better when the limit is short and the pressure is the point; the first is easier to scan when the number is mostly reassurance. Whichever is chosen, it belongs where the eye already is: beside the label or under the box, never across the form.

The counter has an accessibility trap in it. Updating a live region on every keystroke turns typing into a stream of announcements that drown out the letters themselves, so the visible number updates immediately while the announced one waits for a pause in typing. GOV.UK settled this in public, and the pattern of a polite, debounced status message next to a silent visible count is the version worth copying.

Near the limit the counter usually changes register: a colour shift, or the count switching from used to remaining. That is a warning, not an error, and it should stay a warning. The error, if there is one, is what the field does when the limit is passed, and whether it refuses the extra characters or accepts and complains is a decision the counter alone does not make.