Ever wonder when to put a comma before or after "that is" in your sentences? If yes, you're not alone! Many writers get confused about comma placement when using "that is"—a phrase frequently employed to add clarification or extra information. Proper punctuation can make your writing clearer and more professional. In this guide, I’ll walk you through everything you need to know about using commas with "that is," highlighting common mistakes, tips for success, and practical exercises. Let’s dive in!
What is "That Is" and Why Use Commas?
"That is" is a phrase used to clarify, elaborate, or specify something in a sentence. Think of it like adding a little extra info, making your point more precise.
Why use commas?
Commas help separate non-essential information ("that is" clauses) from the main part of the sentence, ensuring readers don’t get confused. The placement of these commas can change the sentence’s meaning or clarity.
When to Use a Comma Before "That Is"
Typically, you do not need a comma before "that is" unless it introduces additional, non-essential info that interrupts the main sentence.
Example 1:
- Correct: "The book that is on the table belongs to Sarah."
- Here, "that is on the table" is essential; removing it would change the meaning.
Example 2:
- Incorrect: "The book, that is on the table, belongs to Sarah."
- Here, the commas incorrectly suggest that the info is non-essential, which it isn’t.
Exception – Non-essential info:
Use a comma before "that is" when the phrase is extra info that can be removed without changing the core sentence.
Example:
- Correct with commas: "My sister, that is a great cook, made dinner."
- Here, "that is a great cook" is extra info, so commas are appropriate.
When to Use a Comma After "That Is"
Generally, you do not put a comma after "that is". If the phrase is at the end of a clause, follow standard punctuation rules—unless it’s introducing a pause for emphasis.
In most cases:
- "The problem that is difficult requires extra attention." (No comma after "that is")
- To add a pause or emphasis: "The problem that is difficult, in fact, requires extra attention."
Key Points Summary
| Context | Comma Before "That Is" | Comma After "That Is" | Notes |
|---|---|---|---|
| Essential (restrictive) clause | No | No | No commas needed; integral to meaning |
| Non-essential (non-restrictive) clause | Yes | No | Use commas to set off extra info |
| Extra info after "that is" for emphasis | Often optional | Optional | For emphasis or pause |
Top 15 Categories Where "That Is" with Commas Makes a Difference
To show you how versatile "that is" can be, here are 15 categories with example sentences demonstrating correct comma usage.
| Category | Example Sentence | Notes |
|---|---|---|
| Personality Traits | "John, that is very kind, opened the door." | Extra info about personality, commas optional depending on emphasis |
| Physical Descriptions | "The painting that is colorful captivated everyone." | No commas, essential info |
| Roles & Jobs | "My uncle that is a chef owns a restaurant." | No comma, essential info |
| Opinions & Judgments | "This idea that is too complicated was rejected." | No comma, essential clause |
| Physical Conditions | "The machine that is broken needs repair." | No comma, essential info |
| Locations | "The city that is famous for art attracts visitors." | No commas, essential info |
| Time & Dates | "The event that is scheduled for tomorrow has been canceled." | No comma, essential info |
| Quantities & Amounts | "The amount that is too high concerns management." | No comma |
| Physical Characteristics | "The dog that is small is adorable." | No comma |
| Personal Traits | "Emma, that is very patient, helped her classmates." | Extra info, commas used |
| Roles & Responsibilities | "The teacher that is strict enforces discipline." | No comma |
| Specific Locations | "The park that is near my house is large." | No comma |
| Preferences & Opinions | "The movie that is interesting won several awards." | No comma |
| Business & Company Names | "Apple that is innovative leads the market." | No comma |
| Emphasized Clarifications | "The problem that is critical, in my opinion, needs urgent action." | Commas for emphasis |
Note: When adding “that is” for extra clarification or as a parenthetical element, using commas enhances readability.
Proper Order & Multiple "That Is" Clauses
When using multiple "that is" clauses, the correct order is crucial for clarity.
Example:
- "The book that is on the shelf, that is dusty, belongs to my sister." (Correct when emphasizing both details separately)
- Keep each clause without overwhelming the sentence. Use commas as needed.
Tip: Break long sentences into shorter ones to improve clarity.
Different Forms and Usage Examples
| Form | Example Sentence | Explanation |
|---|---|---|
| Basic essential clause | "The car that is parked outside is mine." | No commas; essential info |
| Non-essential (extra info) | "My car, that is parked outside, is new." | Commas set off extra info |
| Emphatic clause with pauses | "The issue that is urgent, in fact, needs our attention." | Emphasis with commas |
Tips for Success
- Identify essential vs. non-essential info: Essential info about "what" or "which" should not be set off by commas. Extra details can be.
- Read aloud: Pause naturally at commas. If the pause feels unnecessary, reconsider placement.
- Use punctuation consistently: Follow the rules of restrictive and non-restrictive clauses.
Common Mistakes and How to Avoid Them
| Mistake | How to Correct | Explanation |
|---|---|---|
| Using commas unnecessarily before "that is" in essential clauses | Omit commas in essential clauses | Essential info does not require commas |
| Forgetting commas in non-essential info | Add commas around non-essential "that is" clauses | Clarifies extra info |
| Overusing commas in compound sentences | Keep sentences clear with minimal commas | Avoid cluttering sentences |
Similar Variations & Related Constructions
- Using "which is" instead of "that is" (non-essential)
- Combining "that is" with other parenthetical phrases like "in fact," or "to be honest,"
- Using em dashes or parentheses for extra emphasis or breaks
Example:
- "The project, that is due tomorrow, needs to be prioritized." (formal, with commas)
- "The project— that is due tomorrow— needs to be prioritized." (more informal, with dashes)
Why Is Proper Comma Usage Critical?
Correct comma placement in sentences with "that is" ensures your message is clear, avoids ambiguity, and improves professionalism. It helps your readers quickly grasp what’s essential versus supplementary.
Practice Exercises
Let’s sharpen our skills with some exercises. Try filling in blanks, correcting errors, or identifying proper usage.
1. Fill-in-the-blank
- The book ____ that is on the table belongs to me.
- My friend, ____ that is a talented artist, painted this mural.
2. Error Correction
- Correct the sentence: "The phone, that is on the desk, is ringing."
- Correct the sentence: "The movie that is very popular, won many awards."
3. Identification
- Is the comma placement correct? "The car that is parked outside, is new."
- Why or why not?
4. Sentence Construction
- Rewrite using correct comma placement: "The artist that is famous for modern art has an exhibit."
- Rewrite with added emphasis: "The cake that is delicious, in fact, is my special recipe."
5. Category Matching
Match the sentence with the correct rule.
| Sentence | Essential or Non-essential? | Correct comma use | Explanation |
|---|---|---|---|
| "The teacher that is strict enforces discipline." | Essential | No | Clause is necessary for meaning |
| "My cousin, that is a doctor, lives nearby." | Non-essential | Yes | Extra info |
Final Takeaway
Getting the commas around "that is" right can seem tricky at first, but once you understand the difference between essential and non-essential info, it becomes much easier. Remember: no commas in essential clauses, but include them when adding supplementary details. Practice with real sentences, and you'll improve over time.
In Conclusion
Punctuation, especially commas, is a tiny tool with a big impact! Properly placing commas before and after "that is" helps your writing become clearer and more effective. So, next time you write a sentence with "that is," check if the info is essential or extra — then add or omit commas accordingly. Happy writing!
Want to master more grammar tips? Keep practicing, and soon you’ll be a punctuation pro! Thanks for reading, and don’t forget— clarity in writing starts with good punctuation.