That or Which: Which Is Correct?
Updated · Which One Is Correct editorial team
Quick answer: The choice between that or which depends on the information's importance. Use that for essential clauses that define the noun. Reserve which, surrounded by commas, for non-essential details that merely add color. This distinction keeps your writing precise and professional.
The Short Answer
Use that for essential clauses and which with commas for extra information. This simple rule separates necessary definitions from optional commentary in your sentences.
People confuse these words because both introduce descriptive phrases. Without understanding the difference between restrictive and non-restrictive clauses, writers often swap them interchangeably, leading to ambiguity.
Side-by-Side Comparison
| Form | Status | Use it when |
|---|---|---|
| that | Restrictive | The clause is essential to meaning |
| which | Non-restrictive | The clause adds extra, removable info |
| that | Relative Pronoun | Refers to people or things |
| which | Relative Pronoun | Refers to animals or things |
Correct Example Sentences
- The car that has a flat tire needs immediate repair.
- My laptop, which is three years old, still runs fast.
- The book that you recommended changed my perspective.
- His new job, which pays well, requires long hours.
- The dog that barked all night kept us awake.
- The house, which was built in the eighteenth century, stands tall.
- I need the shirt that matches my pants exactly.
- The museum, which is free on Sundays, attracts many visitors.
- The student that scored highest won the scholarship.
- Her comments, which were quite harsh, hurt my feelings.
Common Mistakes and Fixes
- The car which has a flat tire needs repair.
- The car that has a flat tire needs repair.
- The book that I read was boring.
- The book, which I read, was boring.
- The dog which barked was loud.
- The dog that barked was loud.
- My sister that lives in Paris is visiting.
- My sister, who lives in Paris, is visiting.
- The food which was cold tasted bad.
- The food that was cold tasted bad.
- The project that was delayed is now finished.
- The project, which was delayed, is now finished.
A Quick Test You Can Use
Read the sentence without the clause. If the meaning changes or becomes unclear, use that. If the core message remains intact and the clause just adds flavor, use which. This removal test instantly clarifies the grammatical role.
Related Word Pairs
- Who vs. Whom
- Use who for subjects and whom for objects.
- Its vs. It's
- Its shows possession; it's means it is.
- Affect vs. Effect
- Affect is usually a verb; effect is a noun.
- Then vs. Than
- Then indicates time; than compares items.
- Lay vs. Lie
- Lay requires an object; lie does not.
More Example Sentences
- The recipe that my grandmother shared is a family secret.
- The software, which requires an update, is currently crashing.
- Only the applicant that speaks Japanese will be considered.
- The garden, which blooms in spring, needs more water.
- The signal that connects the devices is very strong.
- The painting, which hangs in the lobby, is original.
- The player that scored the goal celebrated wildly.
- The bridge, which spans the river, is historic.
- The email that arrived this morning contains urgent news.
- The cake, which was baked with love, tasted sweet.
Quick Practice
The movie won the award is a classic.
that
The city, is known for its fog, attracts tourists.
which
The pen I lost was expensive.
that
The hotel, offers free breakfast, is nearby.
which
The song plays on the radio is catchy.
that
The teacher, helped me yesterday, is kind.
which
Frequently Asked Questions
Can I use which for essential clauses?
No, using which for essential clauses is incorrect in formal American English. Reserve which for non-essential details that can be removed without changing the core meaning of the sentence.
Does that work for people?
Yes, that can refer to people in restrictive clauses. However, who is often preferred for people. Use that when the person is defined by an essential action or trait.
Why are commas needed with which?
Commas signal that the clause is non-essential. They tell the reader to pause and treat the information as extra commentary rather than a defining characteristic of the noun.
Is this rule strict in British English?
British English is often more flexible with that and which. However, American English strictly follows the restrictive versus non-restrictive distinction, making this rule crucial for US audiences.
