The expression is “you had better + bare infinitive”, for example: “You had better be good.” In spoken English, the word “had” is usually contracted to apostrophe D: “You’d better.” With this particular expression, the D is often dropped in speech, so it will sound like “You better.” In fact this is just “You had better” with the word “had” elided. Even though elided, the word “had” continues to govern the bare infinitive, which is why we don’t say “you better *are good”.

Hi Vladimir, They have the same meaning of giving a strong advice or warning of an unpleasant result if the advice is not heeded. Therefore, "had better" is often used with imperative verbs such as "complete", " do", "give" and so on. Although "had" is used in the expression, the advice applies to the present or the future. Example: "You had better go now before the the traffic gets too heavy." Some people choose to omit "had" but the meaning stays the same: "You better go now before the traffic gets too heavy." I hope this helps.

The correct expression is "You had better", usually contracted to "You'd better". As Phil has explained, the 'd' sound is often 'lost' in speech, so that it sounds like "You better". As a result, many people, particularly AmE speakers, wrongly assume that the expression is "You better". This is similar to what has happened with "have got". The correct, informal form, as in "You've got a problem" often sounds like "You got a problem", so people assume that this is an alternative. You will hear people say "You better leave", just as you'll hear people say "You got a problem". You'll even see this written. This is very poor English. Do not imitate it.

I think 'you better' came from 'you'd better', which is technically correct, but I think 'you better' is used slightly differently now - like in a dangerous moment: 'Hey, it's late, we better get going' or 'He's going to kill you, you better get out of here' I think 'you'd better' is used as kind of advice, for something that is maybe not a danger right at the moment, like 'You'd better go to the doctor about that' or' 'you'd better call your credit card company to let them know' That's how I think they're used now, anyway. :)

Both are correct and mean the same thing. "You better" is much more common, but it's okay to say either!