How do you know vs What makes you think

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

How do you know

Top 1,000 (very common)

What makes you think

Top 2,000 (common)
Most common: How do you know
 How do you knowWhat makes you think
Pronunciation🇬🇧 //haʊ də juː nəʊ//🇺🇸 //haʊ də ju ˈnoʊ//🇬🇧 //wɒt meɪks jʊ θɪŋk//🇺🇸 //wɑt meɪks jʊ θɪŋk//
MeaningA way to ask someone how they have information or certainty about something.A way to ask someone why they believe something.
ExampleHow do you know he will come?What makes you think that I would lie to you?
RegisterNeutralNeutral
How commonTop 1,000 (very common)Top 2,000 (common)
Collocationshow do you know that, how do you know if, how do you know for sureWhat makes you think that, What makes you think otherwise, What makes you think you know
AntonymsHow do you not know, I have no idea, I am unsure-
Common mistakesOmitting 'do' and saying 'how you know', Not using it as a question, treating it as a statement, Forgetting to use appropriate intonation in questionsUsing 'think' without 'what makes you'—it sounds incomplete., Confusing it with 'What do you think?'—which asks for an opinion rather than reasoning.
Usage notesUse in conversation when asking for the source of someone's information. It's polite in most contexts but avoid using it when someone shares personal feelings or beliefs.Use this phrase when you want to inquire about someone's reasoning or justification for a belief. It's neutral in tone but can be perceived as challenging if used in a certain tone.

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How do you know
What makes you think

Frequently asked questions: How do you know vs What makes you think

What's the difference between How do you know and What makes you think?

How do you know: A way to ask someone how they have information or certainty about something. What makes you think: A way to ask someone why they believe something.

Which is more common: How do you know and What makes you think?

How do you know is the most common in everyday English.

Can you show an example of each?

How do you know: How do you know he will come? What makes you think: What makes you think that I would lie to you?

Can I use How do you know and What makes you think interchangeably?

Not always. How do you know and What makes you think 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.