That vs Whom

When to use each in English, with meaning, register, and examples.

That

High-frequency chunk A1 determiner

Whom

Formal Beyond 10,000 (less common) B2 pronoun

Most formal: Whom Most common: That

	That	Whom
Pronunciation	🇬🇧 /["/ðæt/","/ðəʊz/"]/ 🇺🇸 /["/ðæt/","/ðəʊz/"]/ Hear That	🇬🇧 /["/huːm/"]/ 🇺🇸 /["/huːm/"]/ Hear Whom
Meaning	used to refer to a specific thing or person	Used instead of 'who' when talking about the object of a verb or preposition.
Example	Look at that man over there.	Whom did they invite?
Register	Neutral	Formal
How common	High-frequency chunk	Beyond 10,000 (less common)
CEFR level	A1	B2
Part of speech	determiner	pronoun
Collocations	that is, that way, that means, not that, that much	to whom it may concern, whom do you prefer?, with whom are you talking
Antonyms	this	who
Common mistakes	Confusing 'that' with 'which' in restrictive vs non-restrictive clauses., Using 'that' when the antecedent is a person (use 'who')., Overusing 'that' in sentences, which can make them awkward.	Using 'who' instead of 'whom' in object positions., 'Whom' is often omitted in casual talk., Confusing 'whom' with 'who' when using in questions.
Usage notes	Used to refer to something already mentioned or known. In spoken English, it's often used informally. Be careful not to use it in overly formal writing where specificity is needed.	Use 'whom' in more formal situations or writing. In everyday conversation, many people use 'who' instead. It's often used following prepositions.

Frequently asked questions: That vs Whom

What's the difference between That and Whom?

That: used to refer to a specific thing or person Whom: Used instead of 'who' when talking about the object of a verb or preposition.

Which is more formal: That and Whom?

Whom is the most formal of these.

Which is more common: That and Whom?

That is the most common in everyday English.

Are That and Whom the same CEFR level?

That: A1, Whom: B2 on the CEFR scale.

Can I use That and Whom interchangeably?

Not always. That and Whom are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.