What's happening in here vs What's up?

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

What's happening in here

InformalTop 2,000 (common)

What's up?

InformalTop 2,000 (common)
 What's happening in hereWhat's up?
Pronunciation🇬🇧 //wɒts ˈhæp(ə)nɪŋ ɪn hɪə//🇺🇸 //wɑts ˈhæpənɪŋ ɪn hɪr//🇬🇧 //wɒts ʌp//🇺🇸 //wɑts ʌp//
MeaningWhat is going on here?A casual way to ask someone how they are or what's happening.
ExampleWhen I walked into the room, I asked, 'What’s happening in here?'When I saw my friend, I casually said, 'What's up?'
RegisterInformalInformal
How commonTop 2,000 (common)Top 2,000 (common)
CollocationsWhat's happening lately, What's happening next, What's happening right nowWhat's up, buddy?, What's up, man?, What's up with that?, Hey, what's up?, So, what's up?
AntonymsNothing is happening here, What is not happening in here, What's going on outside-
Common mistakesUsing in a formal context, Not using the contraction 'what's', Mispronouncing 'happening'Using it in a formal meeting where a respectful greeting is expected., Misunderstanding it as a question requiring a detailed answer., Not responding appropriately with a casual reply.
Usage notesUse in casual conversations when you're entering a place or situation to inquire about the current circumstances. It's friendly and relaxed; not suitable for formal settings.Used mainly in casual conversations among friends. It may not be appropriate in formal situations.

See it in real clips

What's happening in here
What's up?

Frequently asked questions: What's happening in here vs What's up?

What's the difference between What's happening in here and What's up??

What's happening in here: What is going on here? What's up?: A casual way to ask someone how they are or what's happening.

Can you show an example of each?

What's happening in here: When I walked into the room, I asked, 'What’s happening in here?' What's up?: When I saw my friend, I casually said, 'What's up?'

Can I use What's happening in here and What's up? interchangeably?

Not always. What's happening in here and What's 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.

Related comparisons