After seven years, The Chicago Manual of Style (aka the Chicago Style Guide) has a new edition.
The 18th edition, released in 2024, brings a range of updates to its guidance on language, punctuation, capitalization, spelling, and citations.
What’s New in the 18th Edition of the Chicago Manual of Style (CMOS 18)?
Here's a look at some of the most notable changes and what you can look forward to.
Inclusive Language Updates
CMOS 18 offers updated recommendations on using inclusive and bias-free language, reflecting a commitment to diversity and respect.
One notable change is that generic singular they is now acceptable even in formal writing when referring to someone whose gender is unknown, unspecified, or deliberately concealed.
For example, you can write, "Someone forgot their coat."
CMOS 18 also covers other aspects of inclusive writing, including when to use person-first or identity-first language and gender-neutral terms.
Title Case Capitalization
A big change in CMOS 18 is that title capitalization of titles.
Prepositions with five letters or more (about, below, while, toward, inside...) are now capitalized in titles.
For example:
A Room with a View (unchanged)
Much Ado About Nothing (previously Much Ado about Nothing)
Updated Spelling and Hyphenation Rules
CMOS 18 has clearer guidelines on spelling and hyphenation, especially for compound words.
For example, ebook and esports are now closed compounds, joining email as exceptions to the usual hyphenation of e-terms.
CMOS 18 also expands its guidance on en dashes. When the names of two or more people form a compound modifier before a noun, an en dash now separates the names rather than a hyphen.
For example:
Epstein–Barr virus (named after two people, so an en dash is used)
Albers-Schönberg disease (named after one person, so a hyphen is used)
Streamlined Citations
Those who spend a lot of time working with citations will appreciate the updated, simplified guidelines for citing online resources, government publications, and multimedia sources.
For bibliography and reference list entries:
List up to six authors.
If a work has more than six authors, list the first three, followed by et al.
For notes and author-date text citations:
List up to two authors.
If a work has more than two authors, list the first author, followed by et al.
Also, the place of publication is no longer required in book citations, and "published by the author" (or “pub. by author” in a note) is now preferred over "self-published" when citing independently published books.
Introducing PerfectIt 6 With CMOS 18 Guidance Built In
PerfectIt is the leading proofreading software for professionals who want to ensure consistency and house style across documents.
The latest version, PerfectIt 6, includes guidance from The Chicago Manual of Style's 18th Edition. CMOS is available in PerfectIt for all users who have an active CMOS Online subscription.
PerfectIt gives you the wisdom of CMOS directly within Microsoft Word. This means it can act as your virtual editorial assistant, checking your documents for style consistency according to CMOS guidelines, without the need to flip through pages or search online.
With PerfectIt, you can:
Ensure Consistency: Identify inconsistencies in spelling, hyphenation, capitalization, and more
Save Time: Quickly address style issues, allowing you to focus on content rather than mechanical checks
Learn and Apply: Access explanations and links to CMOS rules, helping you understand and apply style guidelines effectively
Why This Partnership Matters
The combination of CMOS and PerfectIt is valuable for anyone serious about their writing.
Accessibility: Even if you're new to using CMOS, PerfectIt makes it so much easier to apply professional style standards directly in Microsoft Word.
Confidence: Write and edit knowing you have a tool to help you identify inconsistencies and apply established style guidelines.
Productivity: Spend less time on tedious, repetitive proofreading and more time crafting compelling narratives or persuasive reports
As Benjamin Dreyer, author of Dreyer’s English, affectionately describes in Lit Hub:
"The Chicago Manual of Style is like a very smart and accessible friend who's always ready to help."
Interested in the behind-the-scenes journey of integrating CMOS 18 into PerfectIt 6?
Check out our blog post, “Behind the Style: Delivering The Chicago Manual of Style’s 18th Edition in PerfectIt” which details the collaboration and technical innovations that shaped this exciting release.
Keep Your Documents Consistent With PerfectIt
CMOS 18 brings you up-to-date with the very latest language practices, and PerfectIt integrates these standards directly into your writing process.
It’s time to revitalize your writing, enhance your professionalism, and let PerfectIt do the heavy lifting for you.
Try PerfectIt for free for 14 days or book a demo with the team.
Frequently Asked Questions
What Are the Major Changes in CMOS 18?
Some of the major changes in CMOS 18 include accepting singular they in formal writing, capitalizing prepositions with five or more letters in titles, updating spelling and hyphenation rules, expanding en dash guidance, and revising author listings in citations.
Does PerfectIt Support CMOS 18?
Yes. PerfectIt 6 incorporates guidance from CMOS 18 into its Microsoft Word add-in. It reads your entire document and flags inconsistencies with CMOS 18 for your review. You can then decide whether to accept or reject each suggested change.
Do You Need a CMOS Online Subscription To Use Chicago Style in Perfectit?
Yes. You need an active CMOS Online subscription linked to your PerfectIt license to use the Chicago style in your Microsoft Word documents.