Cool MateHey vs What up
When to use each in English, with meaning, register, and examples.
Hey
InformalTop 1,000 (very common)A1exclamation
What up
InformalTop 2,000 (common)
Most common: Hey
| Hey | What up | |
|---|---|---|
| Pronunciation | 🇬🇧 /["/heɪ/"]/🇺🇸 /["/heɪ/"]/ | 🇬🇧 //wɒt ʌp//🇺🇸 //wɑt ʌp// |
| Meaning | A casual greeting used to say hello. | A casual greeting or question asking how someone is doing. |
| Example | Hey, can I just ask you something? | When I saw my friend, I said, 'What up!' |
| Register | Informal | Informal |
| How common | Top 1,000 (very common) | Top 2,000 (common) |
| CEFR level | A1 | - |
| Part of speech | exclamation | |
| Collocations | say hey, hey there, hey buddy, hey dude | What up with you?, Say what up, What up homie |
| Antonyms | goodbye, farewell, bye | - |
| Common mistakes | Using 'hey' in formal emails or letters., Spelling it as 'hay' when greeting someone. | Using 'What up?' in formal emails., Confusing with 'What's up?' which is more common., Not using it with close friends or people you know well. |
| Usage notes | Primarily used in informal situations among friends or acquaintances. It's less appropriate in formal contexts or professional settings. Avoid using it with people you don't know well. | Used among friends or acquaintances in casual settings; not appropriate for formal occasions. |
See it in real clips
Frequently asked questions: Hey vs What up
What's the difference between Hey and What up?
Hey: A casual greeting used to say hello. What up: A casual greeting or question asking how someone is doing.
Which is more common: Hey and What up?
Hey is the most common in everyday English.
Can you show an example of each?
Hey: Hey, can I just ask you something? What up: When I saw my friend, I said, 'What up!'
Can I use Hey and What up interchangeably?
Not always. Hey and What up 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.