Hey vs Hi

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

Hey

Informal Top 1,000 (very common) A1 exclamation

Hi

Informal High-frequency chunk A1 exclamation

	Hey	Hi
Pronunciation	🇬🇧 /["/heɪ/"]/ 🇺🇸 /["/heɪ/"]/ Hear Hey	🇬🇧 /["/haɪ/"]/ 🇺🇸 /["/haɪ/"]/ Hear Hi
Meaning	A casual greeting used to say hello.	A casual way to greet someone.
Example	Hey, can I just ask you something?	Hi guys!
Register	Informal	Informal
How common	Top 1,000 (very common)	High-frequency chunk
CEFR level	A1	A1
Part of speech	exclamation	exclamation
Collocations	say hey, hey there, hey buddy, hey dude	say hi, wave hi, hi there
Antonyms	goodbye, farewell, bye	bye, goodbye, farewell, see you
Common mistakes	Using 'hey' in formal emails or letters., Spelling it as 'hay' when greeting someone.	Using 'hi' in overly formal contexts., Spelling it as 'hey' which is more informal., Confusing with 'hello' which is slightly more formal.
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 and in casual settings. Avoid in formal situations like interviews or professional meetings.

Frequently asked questions: Hey vs Hi

What's the difference between Hey and Hi?

Hey: A casual greeting used to say hello. Hi: A casual way to greet someone.

Are Hey and Hi the same CEFR level?

Hey: A1, Hi: A1 on the CEFR scale.

Can I use Hey and Hi interchangeably?

Not always. Hey and Hi 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.