About

Incorrect title capitalization undermines credibility. A post titled "How to build A better Api" signals carelessness to readers and search engines alike. The problem is that no single rule exists. AP Stylebook lowercases prepositions of three or fewer letters; Chicago Manual of Style lowercases prepositions of four or fewer. APA 7th edition capitalizes words of four or more letters regardless of part of speech. This tool applies 5 major style guides - AP, APA, Chicago, MLA, and Wikipedia - and highlights every word it corrects so you can see exactly what changed.

The engine handles edge cases most tools ignore: hyphenated compounds (e-commerce vs. Self-Driving), words after colons, first and last word rules, and intentional all-caps preservation for acronyms like NASA or API. Limitation: the checker uses lexical rules, not natural language parsing. It cannot distinguish the verb "to run" from the noun "a run" - both are treated identically. For most blog titles, lexical rules achieve over 95% accuracy.

Formulas

The capitalization engine applies a deterministic rule chain to each word w at position i in a title of n words:

{

uppercase(w) if i = 0 or i = n − 1preserve(w) if w ∈ ACRONYMSlowercase(w) if w ∈ S_styleuppercase(w) if w ∈ VERBS ∪ PRONOUNScapitalize(w) otherwise

Where w is the current word, i is its zero-based index, n is the total word count, S_style is the set of lowercase exception words for the active style guide, ACRONYMS is the set of all-uppercase words (detected when all characters are uppercase and length ≥ 2), and capitalize uppercases only the first letter. For hyphenated words, the engine splits on - and applies the rule chain recursively to each segment, respecting style-specific hyphenation rules.

Reference Data

Rule	AP Stylebook	APA 7th Ed.	Chicago (CMOS 17)	MLA 9th Ed.	Wikipedia (WP:TITLE)
First word capitalized	Always	Always	Always	Always	Always
Last word capitalized	Always	Always	Always	Always	No special rule
Articles (a, an, the)	Lowercase	Lowercase	Lowercase	Lowercase	Lowercase
Short prepositions threshold	≤ 3 letters	< 4 letters	≤ 4 letters (traditional)	Lowercase all	Lowercase all
Coordinating conjunctions	Lowercase (and, but, or, for, nor, so, yet)	Lowercase (and, but, or, nor, so, yet)	Lowercase (and, but, or, for, nor, so, yet)	Lowercase	Lowercase
"to" as infinitive marker	Lowercase	Lowercase	Lowercase	Lowercase	Lowercase
Words ≥ 4 letters	Capitalize	Capitalize	Capitalize (major words)	Not the sole rule	No length rule
Hyphenated compounds	Capitalize first element; lowercase articles/short preps	Capitalize both elements	Capitalize major elements	Capitalize all elements	Capitalize first only
After colon	Capitalize if complete sentence	Always capitalize	Always capitalize	Capitalize	Capitalize
"is", "are", "be" (verbs)	Capitalize	Capitalize	Capitalize	Capitalize	Capitalize
"it", "he", "my" (pronouns)	Capitalize	Capitalize	Capitalize	Capitalize	Capitalize
"vs." / "versus"	Lowercase (prep)	Lowercase	Lowercase	Lowercase	Lowercase
"between", "through"	Capitalize (> 3 letters)	Capitalize (≥ 4)	Lowercase (preposition)	Lowercase (preposition)	Lowercase
Species/Latin terms	Follow convention	Follow convention	Italicize, follow convention	Follow convention	Follow convention
Acronyms (NASA, API)	Preserve all-caps	Preserve all-caps	Preserve all-caps	Preserve all-caps	Preserve all-caps

Frequently Asked Questions

All five supported style guides classify "is", "be", "am", "are", and "was" as verbs. Verbs are always capitalized in title case regardless of length. The word-length threshold (3 or 4 letters depending on the guide) applies only to prepositions, conjunctions, and articles - never to verbs or pronouns.

The behavior differs by style guide. APA 7th edition capitalizes both elements of a hyphenated compound (Self-Driving). Chicago capitalizes major elements but lowercases articles and short prepositions within the compound. MLA capitalizes all elements. AP capitalizes the first element and applies standard rules to subsequent elements. The tool splits on the hyphen, applies the active guide's rules to each segment, then rejoins.

Automatic detection. Any word where all alphabetic characters are uppercase and the word is 2 or more letters long is treated as an acronym and preserved as-is. This means NASA, API, HTML, and CEO remain fully capitalized. If you type a regular word in all caps (e.g., "VERY"), it will also be preserved. To override, type it in lowercase and let the tool capitalize it per the rules.

APA and Chicago always capitalize the first word after a colon. AP capitalizes only if the text after the colon is a complete sentence. MLA capitalizes. For em-dashes, the first word after is capitalized in Chicago and APA. The tool detects colons (:) and em-dashes (- or --) as clause boundaries and applies the first-word rule to the next token.

AP Stylebook is the most common choice for journalism, blogs, and marketing content. APA is standard in academic and scientific writing. Chicago is preferred in book publishing and long-form editorial. MLA is used in humanities academic papers. Wikipedia style is relevant if you contribute to or cite Wikipedia. For general blog posts, AP is the safest default.

No. The engine uses lexical classification, not syntactic parsing. The word "with" is always classified as a preposition. Similarly, "run" is classified based on its entry in the short-word exception list, not by context. This is a known limitation of rule-based title casing. For blog titles - which are typically short and structurally simple - this approach is reliable in over 95% of cases.