When writing names that end with an “s”, many people get confused about how to make them possessive. One of the most common examples is Lucas’s or Lucas’ — but which one is correct? Both forms can appear in writing, yet the choice often depends on style guides, pronunciation, and personal preference. Let’s explore the difference in detail so you can use the right form with confidence.

Basic Meaning

Both Lucas’s and Lucas’ show possession—they mean something belongs to Lucas.

• Lucas’s is the modern, standard form of the possessive. 
• Lucas’ is a simpler, alternative form often used in journalism or older English.
  

Example:

• Lucas’s car = The car belongs to Lucas. 
• Lucas’ car = The same meaning—the car belongs to Lucas. 

So, both are correct in meaning, but they differ in style and usage.

Related: Signer or Signor

Understanding Possessive Forms of Proper Nouns

To show ownership or possession, English adds ’s to a singular noun.
For example:

• The cat’s toy → The toy belongs to the cat. 
• James’s car → The car belongs to James.
  

But what happens when a name already ends with s, like Lucas, James, or Charles? That’s where the confusion between Lucas’s or Lucas’ comes in.

The General Grammar Rule

According to modern grammar rules, you should add ’s to any singular noun, even if it ends with an s.
Lucas’s book → means the book belonging to Lucas.

This form is recommended by major style guides such as:

• The Chicago Manual of Style (CMOS) 
• The Modern Language Association (MLA)
  

Both suggest that Lucas’s is the correct possessive form because it reflects how the name is pronounced: Loo-kus-iz.

When to Use “Lucas’”

The shorter version, Lucas’, is also seen, especially in journalistic writing or older British English.
Some people prefer Lucas’ because it looks cleaner and avoids what they see as an extra “s.”

Examples:

• Lucas’ homework (acceptable in Associated Press (AP) style) 
• Jesus’ teachings (a traditional exception due to religious and historical use)
  

So, if you’re writing for a newspaper or following AP style, Lucas’ might be the preferred choice.

Pronunciation Difference

Whether you write Lucas’s or Lucas’, most people pronounce it the same way:
  Loo-kus-iz.

That’s why many grammar experts argue that Lucas’s is clearer — because the spelling matches the pronunciation.

Comparison Table

Style Guide / Context	Preferred Form	Example
Chicago Manual of Style	Lucas’s	Lucas’s car
MLA (Academic Writing)	Lucas’s	Lucas’s essay
AP Style (Journalism)	Lucas’	Lucas’ opinion
British English (Traditional)	Lucas’	Lucas’ house

Quick Tip for Remembering

• If you say the extra “iz” sound, write Lucas’s. 
• If you don’t say the extra sound, or are following AP style, write Lucas’. 

Both are grammatically acceptable — the key is consistency within your writing.

Examples in Sentences

1. Lucas’s car was parked outside the school. 
2. Everyone admired Lucas’s painting at the art show. 
3. According to the article, Lucas’ decision changed the company’s future. 
4. Lucas’s performance in the play was outstanding. 
5. The teacher returned Lucas’ notebook after grading it. 

Final Thoughts

What’s the correct form — Lucas’s or Lucas’? Both are right, but they fit different writing styles.

• Use Lucas’s if you follow modern grammar rules (Chicago, MLA, academic, or general writing). 
• Use Lucas’ if you follow journalistic (AP) style or prefer a simpler appearance. 

The most important rule is consistency — whichever form you choose, stick with it throughout your writing.

In short, when deciding between Lucas’s or Lucas’, both forms show possession, but Lucas’s is the more widely accepted modern form.