Informal:
* 你好 (nǐ hǎo): This is the most common and versatile greeting, suitable for most situations. It literally means "you good," but translates to "hello" or "hi" in English.
* 嗨 (hāi): This is a more casual and friendly greeting, similar to "hey" in English.
* 喂 (wèi): This is a very informal greeting, often used when answering the phone or calling someone over. It's similar to "yo" in English.
Formal:
* 您好 (nín hǎo): This is a more respectful greeting, used when addressing someone older, of higher status, or someone you don't know well. It literally means "you good" but conveys more respect than "你好."
The best translation for "hi" depends on the specific situation and your relationship with the person you're greeting.