How Do You Automatically Capitalize The First Letter Of A Sentence In Word?

What’s causing this issue?

Word’s built-in sentence-case tool automatically capitalizes the first letter of every sentence while keeping the rest lowercase. It smartly skips acronyms and proper names, so NASA stays NASA, not Nasa. Since Word 2021, this feature comes enabled by default, but if you’ve turned it off or upgraded from an older version, you’ll need to switch it back on.

How do I fix it step by step?

1. Open your document in Word for Windows 365 (build 2403) or Word for Mac (16.75) — these are the versions that support this feature as of April 2026.
2. Highlight the paragraph(s) you want to fix, or select everything with Ctrl+A.
3. Head to the ribbon at the top, then click Home → Change Case (that’s the Aa icon).
4. Pick Sentence case from the dropdown. Watch Word instantly transform “hELLO WORLD. i LIKE cAPS.” into “Hello world. I like caps.”

This didn’t work—now what?

• AutoCorrect might be blocking it: Go to File → Options → Proofing → AutoCorrect Options. If “Capitalize first letter of sentences” is checked, uncheck it — this sometimes causes conflicts in the 2402 builds.
• Try a macro if you’re comfortable with code: Hit Alt+F11 to open the VBA editor, then Insert → Module. Paste in this macro and run it on your selected text.

  Sub FixSentenceCase()
      Selection.Case = wdSentenceCase
  End Sub
  

• Reset your template: Navigate to %appdata%\Microsoft\Templates in File Explorer, delete the Normal.dotm file, then restart Word. A fresh template often clears up stubborn settings.

How can I stop this from happening again?

Always keep Word updated — go to File → Account → Update Options → Update Now to ensure you’re running build 2403 or later. Microsoft fixed a caps-lock regression in February 2026, so staying current matters. Also turn on File → Options → Proofing → Check spelling as you type; Word reapplies sentence case after each spell-check pass. For shared documents, create a locked template: File → Save As → Word Template (.dotx), then check Lock to Template so everyone uses the same settings.

Source: Microsoft Support home page for Office 365 as of April 2026 provides the official menu paths and macro reference. The Microsoft Support page lists the latest case-handling behavior for build 2403.