Capitalization of Acronym Expansions
Capitalization of Acronym Expansions explains Microsoft’s rule that acronym letters do not by themselves justify capitalizing the spelled-out words.
Do not capitalize a spelled-out acronym expansion just to match the acronym’s capitals; keep ordinary words lowercase unless they are proper nouns.
Key details
Important caveats
Scope Boundary
This is a capitalization rule for ordinary expansions, not a direction to lowercase official proper names.
Further guidance
Content
Lowercase ordinary words in a spelled-out acronym expansion; retain capitalization required by proper nouns.
Purpose
Avoid false title-style capitalization created only to mirror an acronym’s uppercase letters.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Acronyms checklist — Microsoft Style Guide (opens in a new tab)Microsoft · Microsoft technical-style checklist for first-use acronym expansion and capitalization of spelled-out forms
- Capitalization — Microsoft Style Guide (opens in a new tab)Microsoft · Microsoft technical-style guidance for sentence-style headings, acronym expansion capitalization and capitalization after colons