You know vs You know what that is

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

You know

InformalTop 2,000 (common)

You know what that is

Top 2,000 (common)
Most formal: You know what that is
 You knowYou know what that is
Pronunciation🇬🇧 //jʊ nəʊ//🇺🇸 //juː noʊ//🇬🇧 //juː nəʊ wɒt ðæt ɪz//🇺🇸 //ju noʊ wɒt ðæt ɪz//
MeaningA phrase used when you think the listener understands or agrees.A phrase used to confirm understanding or knowledge about something.
ExampleIt's like when you're at a party, and, you know, the music just hits differently.She opened the box, looked at the contents, and exclaimed, 'You know what that is!'
RegisterInformalNeutral
How commonTop 2,000 (common)Top 2,000 (common)
Collocationsyou know what I mean, you know how, you know the drillYou know what I mean, You know the drill, You know the score
Common mistakesUsed too frequently, making speech sound repetitive., Assuming the listener always knows what is being referred to., Overusing it can make speech less clear.Misuses the phrase in formal settings., Forgets to use appropriate intonation to convey meaning., Uses it without context, making it unclear.
Usage notesCommon in casual conversations to imply shared understanding. Should be avoided in formal settings.Used in informal conversations to emphasize shared understanding; may not be appropriate in formal contexts.

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You know
You know what that is

Frequently asked questions: You know vs You know what that is

What's the difference between You know and You know what that is?

You know: A phrase used when you think the listener understands or agrees. You know what that is: A phrase used to confirm understanding or knowledge about something.

Which is more formal: You know and You know what that is?

You know what that is is the most formal of these.

Can you show an example of each?

You know: It's like when you're at a party, and, you know, the music just hits differently. You know what that is: She opened the box, looked at the contents, and exclaimed, 'You know what that is!'

Can I use You know and You know what that is interchangeably?

Not always. You know and You know what that is 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.

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