The Presumptive Proofreader
Google Docs features an aggressive autocorrect engine designed to catch common formatting and grammatical errors. Because a colon is frequently used to introduce a formal list or a distinct, independent clause, Google Docs will sometimes assume that the word immediately following the colon represents the start of a new, formal sentence. Consequently, it will automatically capitalize the first letter of that word. While this might align with certain style guides, it is incredibly frustrating if you are typing computer code, JSON payloads, time formats, or ratios where a lowercase letter is strictly required immediately after the colon.
Overriding the Auto-Capitalization Rule
To maintain exact control over your document’s casing and stop Google Docs from automatically capitalizing words after colons, you must disable the global capitalization preference.
Unfortunately, Google Docs does not have a granular setting specifically labeled “capitalize after colons”; the behavior is governed by the broader sentence capitalization rule. Open your Google Docs document. In the top menu bar, click on Tools and select Preferences from the dropdown list. A dialogue box will appear. Ensure you are on the General tab. Locate the checkbox labeled Automatically capitalize words. By default, this box is checked. Simply click the checkbox to uncheck it, and then click the blue OK button to save your changes. While this will stop the capitalization after colons, be aware that it will also stop Google Docs from capitalizing the first word of standard sentences after a period, meaning you will need to rely entirely on your own manual Shift-key usage.