Design Capitalization and Casing Rules

Content & UX Writing · microcopy, consistency, design systems

Updated 2026-07-28

Pick one casing convention for the product and write it down. Inconsistent capitalisation is the fastest way to make a careful interface look unfinished.
Prefer sentence case for almost everything. It is easier to read, easier to translate, and it removes the endless argument about which words in a title are important.
Reserve capitals for names. Product names, plan names, and features that are genuinely proper nouns get a capital, and ordinary words do not become important by receiving one.
Never use uppercase for long strings. Full capitals remove the word shapes readers rely on, so keep them for short labels only.
Set the casing in the design, not in the content. Transforming text visually keeps the underlying string readable for screen readers, search, and copy and paste.
Remember that casing is language-specific. Automatic transforms break in languages with different rules, and some scripts have no cases at all.
Apply the same rule everywhere the string appears. A button, its tooltip, the confirmation toast, and the audit log entry should not each have their own style.
Keep acronyms consistent and spell them out on first use. Half the readers of an internal tool do not know what the abbreviation means.

Casing is a small rule that touches every string in the product, which is why it is worth deciding once instead of per screen.