Picking between AP Style vs Chicago Style can feel like being forced to choose a team you didn’t sign up for. One’s blunt and made for speed, the other’s polished with a love for formality, and both will correct you with a straight face.
In this guide, you’ll get a sharp, side-by-side breakdown of AP Style vs. Chicago Style, including who uses them, when to stick to one, and how to stay consistent without losing your voice.
AP Style and Chicago Style weren’t built to compete, but their rules often clash in the hands of writers, editors, and brands. This section breaks down the most telling differences so you’re not stuck second-guessing commas or formatting choices.
AP Style
Chicago Style
Numbers: Spells out 1–9, numerals for 10+
Numbers: Spells out 1–100 in general prose
Titles: Capitalize only when title comes before a name
Titles: Capitalize formal titles in most contexts
Possessives Ending in “s”: Add just an apostrophe (James’)
Possessives Ending in “s”: Add apostrophe + “s” (James’s)
Em Dashes: Use space-hyphen-space format
Em Dashes: Use actual em dash with no spaces
Oxford Comma: Omit the final comma unless needed for clarity
Oxford Comma: Always include the Oxford comma
Accents: Remove most accents unless essential
Accents: Retain all original accents and diacritics
Ellipses: Three spaced dots: “ . . . ”
Ellipses: Tighter structure or single glyph: “…”
Title Case Capitalization: Lowercase short prepositions and conjunctions (<4 letters)
Title Case Capitalization: Capitalize all major words, including long prepositions and subordinating conjunctions
Numbers
AP Style spells out numbers from one through nine and uses numerals for 10 and above. Chicago Style takes a more traditional route, spelling out numbers from one through one hundred in most general text.
Numerals are only introduced in Chicago when dealing with scientific content, statistical comparisons, or consistency within a dense numeric passage. This one rule sets the pace of a paragraph, AP reads faster, while Chicago offers a smoother, bookish rhythm.
Example:
AP: “She adopted 7 cats and 11 dogs.”
Chicago: “She adopted seven cats and eleven dogs.”
The difference here isn’t just visual, it’s contextual. If you’re writing for digital media, fast-paced marketing, or PR content, numerals help readers scan quickly and absorb information faster. That’s AP’s core value: speed meets structure.
Chicago, however, aims for a refined, uninterrupted reading experience. Its spelled-out numbers slow the eye just enough to preserve elegance and tonal consistency. For essays, books, or research-heavy materials, it holds its ground beautifully.
Titles
AP Style lowercases job titles unless they directly precede a person’s name. For instance, “governor” stays lowercase in “the governor spoke” but is capitalized in “Governor Smith spoke.”
Chicago Style, on the other hand, generally capitalizes formal titles across the board, especially when the subject is being formally presented or identified in professional writing. The difference speaks volumes about each style’s view of hierarchy and tone.
Example:
AP: “The mayor, Linda Ortiz, will attend.”
Chicago: “The Mayor, Linda Ortiz, will attend.”
In journalism or social media copy, lowercasing titles reduces visual clutter and creates a more relaxed, even tone. AP assumes familiarity, it reads like a conversation, not a press briefing.
Chicago’s choice to capitalize signals status and formality, which aligns with academic publications, government reports, or biographies.
So if you’re writing a university press release or formatting your company’s annual report, Chicago’s treatment gives that polished, elevated finish that AP deliberately avoids.
Possessive Apostrophes with Singular Proper Nouns Ending in “s”
Here’s where AP and Chicago split cleanly over punctuation purism. AP Style adds only an apostrophe after a singular proper noun ending in “s” (e.g., James’), while Chicago Style insists on adding both the apostrophe and an additional “s” (e.g., James’s).
The rationale isn’t about rules for the sake of rules, it’s about how each style hears and respects spoken rhythm versus visual minimalism.
Example:
AP: “James’ notes were missing.”
Chicago: “James’s notes were missing.”
In AP, the apostrophe-only version trims unnecessary visual elements and plays to the speed of reading, less ink, more scan. It’s common in headlines, captions, and news blurbs where extra characters can crowd the text.
Chicago doubles down on grammatical completeness and favors phonetic consistency. If you’d pronounce the extra “s,” it should be written, simple as that.
This choice feels minor, but once you’re writing 40,000 words with repeated names, it makes a tangible impact on tone and pacing.
Em Dashes
AP Style avoids typographic em dashes entirely. Instead, it uses a standard dash flanked by spaces, like this: space-hyphen-space.
Chicago Style embraces the true em dash without spaces on either side, treating it as a formal punctuation mark designed to control rhythm and tone. Visually, this makes AP more utilitarian, while Chicago leans into classic print aesthetics.
Example:
AP: “They made a decision – one that surprised everyone.”
Chicago: “They made a decision—one that surprised everyone.”
The space-hyphen-space version in AP is pragmatic, especially in environments where special characters might render poorly, think email, SMS, or old-school CMS editors.
It’s functional, not fancy. Chicago, in contrast, assumes a proper typesetting environment and rewards careful writing with clean, professional typography.
If you’re writing for publication or laying out print content, the em dash sharpens the visual and gives your sentence real momentum. Use AP when compatibility matters; use Chicago when design and flow come first.
Oxford Comma
AP Style drops the Oxford comma, the final comma in a list, unless its absence creates confusion. Chicago Style uses it religiously, placing a comma before the conjunction in every list of three or more items.
This single punctuation mark has been at the center of lawsuits, brand guidelines, and editorial throwdowns, but the underlying logic is simple: AP trusts context; Chicago trusts structure.
Example:
AP: “She brought snacks, drinks and napkins.”
Chicago: “She brought snacks, drinks, and napkins.”
AP’s approach reflects journalism’s efficiency obsession. Fewer characters mean faster production, tighter columns, and cleaner visuals.
It’s perfect for breaking news, social media captions, or quick product descriptions where brevity is critical. Chicago, meanwhile, bets on precision.
That one extra comma removes ambiguity and supports parallel structure. If you’re writing legal content, instructional guides, or academic text, leaving it out can feel sloppy. In most professional publishing, Chicago’s extra comma is the gold standard for clarity.
Accents
AP Style removes most foreign accents or diacritics unless they are essential to comprehension or widely recognized, think Beyoncé or El Niño.
hicago Style keeps all original marks intact, treating them as a matter of editorial integrity, accuracy, and cultural respect. This isn’t a stylistic opinion, it’s a practical reflection of where your content will live and who it’s for.
Example:
AP: “Jose Andres will appear.”
Chicago: “José Andrés will appear.”
AP assumes your content may be republished, emailed, or rendered on platforms that struggle with special characters. Removing accents avoids technical issues and keeps things universally readable. It’s utilitarian, but not careless.
Chicago, in contrast, assumes a controlled publishing environment and expects readers to value linguistic precision.
If you’re referencing international names, academic texts, or original titles in foreign languages, preserving accents aligns with professionalism and credibility. It’s not just about spelling, it’s about showing you care enough to get it right.
Ellipses
AP Style breaks ellipses into three spaced periods, with a space before and after the series: space-dot-space-dot-space-dot-space. Chicago Style treats ellipses as a unified visual mark, often using a single-character glyph or unspaced series depending on the sentence structure.
This changes the pacing of your writing, AP is cleaner, Chicago is moodier.
Example:
AP: “I just don’t know . . . it feels off.”
Chicago: “I just don’t know… it feels off.”
The AP format was designed for manual typewriters and digital platforms that default to basic character sets. Its spacing makes omissions obvious and maintains quote clarity, especially in reporting. Chicago, on the other hand, leans into narrative rhythm and aesthetic flow.
The tighter ellipsis works well in fiction, essays, or introspective writing where pauses carry emotional weight. If you want literal clarity, go AP. If you’re aiming for stylistic nuance, Chicago’s formatting lets the silence speak.
Title Case Capitalization
AP Style capitalizes the first and last words of a title, along with all major words, but it lowercases articles, short conjunctions, and prepositions under four letters. Chicago Style capitalizes all significant words, including long prepositions and subordinating conjunctions.
The results may look similar at a glance, but in formal documents or page layouts, the difference becomes clear.
Example:
AP: “How to Manage Stress at Work”
Chicago: “How to Manage Stress at Work”
AP’s structure emphasizes readability and uniformity, particularly in headlines and subheadings where space and font size matter. It’s engineered for publications, web platforms, and marketing content where visual flow trumps tradition.
Chicago takes the high road of literary consistency. It reflects deep formatting discipline, ideal for books, research titles, and academic work where precision and typographic elegance are expected. In short: AP keeps it functional, Chicago makes it formal.
Need help crafting content that fits your chosen style? Let the HelperX Bot AI assistant at helper.techhelp.ca streamline your writing. Whether you’re publishing a press release or formatting a white paper, HelperX can generate polished, on-brand content that aligns with AP or Chicago standards.
Where AP and Chicago Agree (Yes, It Happens)
Not every grammar rule sets these two apart. In fact, some foundational standards are shared across both because they simply work.
Periods and Commas Inside Quotation Marks
Both AP and Chicago place periods and commas inside quotation marks, regardless of logic or how the sentence reads aloud. This rule prioritizes clean typography and avoids visual disruption at the end of quoted text.
It can feel counterintuitive for new writers who want punctuation outside the quotes, but in both guides, internal placement is the rule. That consistency makes it one less thing to worry about across platforms or document types.
Example:
AP: She called it “a total win.”
Chicago: She called it “a total win.”
Capitalizing Proper Nouns
Both styles agree that proper nouns should always be capitalized. This includes names of people, cities, companies, historical events, and branded terms.
You won’t find any difference here, it’s a universal rule grounded in clarity and respect for identity. If it’s a name or unique title, you capitalize it. Simple.
Example:
AP: They toured the White House before heading to Starbucks.
Chicago: They toured the White House before heading to Starbucks.
Quotation Marks for Direct Quotes
AP and Chicago both use double quotation marks for direct quotes and single quotation marks for quotes within quotes. This applies to dialogue, interview content, and any form of verbatim speech.
The rule holds up whether you’re writing a news article or a history paper, it keeps structure clean and prevents confusion in nested quotes. It’s one of the most widely followed rules in English style guides for good reason.
Example:
AP: “Did she really say, ‘I’m not interested’?” he asked.
Chicago: “Did she really say, ‘I’m not interested’?” he asked.
Apostrophes in Contractions
Both styles use apostrophes to mark omitted letters in contractions and informal speech. This includes common phrases like don’t, can’t, it’s, and they’ve.
There’s no variation in spelling or placement between AP and Chicago, both treat contractions as standard in conversational and general-purpose writing.
They only diverge when contractions affect possessives (see previous section), not when it comes to basic usage.
Example:
AP: It’s been a long day, and she doesn’t want to go out.
Chicago: It’s been a long day, and she doesn’t want to go out.
Consistent Use of Singular “They”
While this rule is newer, both AP and Chicago now officially recognize the use of singular “they” as grammatically acceptable. It can refer to a person whose gender is unknown, nonbinary, or irrelevant to the context.
Both styles updated their guidance to reflect inclusivity, modern usage, and what real people are actually saying. In clear, intentional writing, singular “they” avoids awkward phrasing without losing clarity.
Example:
AP: If a client calls, they’ll get a response within 24 hours.
Chicago: If a client calls, they’ll get a response within 24 hours.
Choosing the Right Style for Business Writing
Your brand’s credibility can hinge on consistency, and that includes how you write. Choosing between AP and Chicago Style in business isn’t about preference, it’s about purpose, audience, and format.
Use AP Style for External Communications and Media Content
AP Style is the go-to for press releases, blog posts, newsletters, and social media updates. Its clean, punchy format matches how people consume content in short bursts, fast, skimmable, and accessible.
If your business works with journalists, PR firms, or publishes news-driven content, AP helps you speak their language. It also aligns with how search engines scan content, so your online writing stays sharp and easy to index.
Use Chicago Style for Internal Documents, Reports, and Formal Publications
Chicago Style excels in business writing that requires depth, precision, or formal structure. Think annual reports, internal white papers, case studies, or research-backed presentations.
Its strict rules create consistency in long-form content, especially when footnotes, citations, or multi-section formatting are involved. Chicago signals polish and thoroughness, ideal for board-facing content, investor materials, or published thought leadership pieces.
Example Uses:
Investor decks and executive summaries
Industry white papers with supporting citations
Technical documentation or employee handbooks
Professional bios and book-length leadership content
When crafting formal documents or internal reports, having Sintra’s innovative business process tools in your workflow can streamline collaboration and formatting. It pairs well with the structured nature of Chicago Style writing.
When You’re Switching Styles, Define a Style Guide for Your Team
If your business uses both styles across departments or formats, it’s critical to build a basic in-house guide. That way, marketing isn’t clashing with product teams, and leadership memos don’t contradict public-facing language.
Choose one default, define the exceptions, and include examples of how to handle numbers, punctuation, and titles. Consistency beats perfection, pick what fits your workflow and stick with it.
If your team manages content across different platforms, HubSpot CRM’s integrated marketing and documentation tools can help enforce brand voice and writing style across departments. It’s ideal for teams balancing both AP and Chicago guidelines.
Final Call: Pick Your Style, Then Own It
AP and Chicago aren’t rivals, they’re tools for different kinds of communication. If you’re writing fast, public-facing content, AP keeps it sharp and reader-friendly.
For anything formal, long-form, or designed to show authority, Chicago brings structure and depth. Choose the one that fits your message, commit to it, and let consistency do the heavy lifting.
Consistency starts with great tools. Use the HelperX Bot AI assistant to generate clear, on-style content for blogs, reports, or social posts, no style guide second-guessing needed.
Frequently Asked Questions
Can you mix AP Style and Chicago Style in the same document?
Mixing AP and Chicago in a single document isn’t recommended, especially in professional or branded content. Switching styles midstream can create inconsistencies that confuse readers and reflect poorly on your editorial process or brand clarity.
Is one style more accepted globally than the other?
Neither style dominates globally, but Chicago tends to be more recognized in international academic and publishing circles. AP is tightly tied to American journalism and may feel unfamiliar or informal to non-U.S. readers in formal business or academic settings.
Do software tools support both AP Style and Chicago Style?
Most grammar and style-checking tools support both, but few enforce them perfectly. Platforms like Grammarly, ProWritingAid, and Microsoft Editor can help, but final accuracy still requires a basic understanding of the rules you’re following for each style.
