In the State of New York, the equivalent of A levels would be passing the Regent’s exam in the various subjects given, and they’re not nearly in as many subjects as in the English system. But I’d consider passing a Regent’s only a little bit better than if you just graduate high school. Some high schools offer the IB, but very few.
It was – and is – better if you go to a certain type of high school, either an independent (or “private”) school or a state-run (“public”) school in a wealthy district. Once in such a public school, you would need to take Advanced Placement courses. The public schools here have a vague equivalency to the comprehensive and grammar schools I’ve read that England used to have.
To get into a good uni here, one either takes the ACT (American College Test) or the SAT (Scholastic Aptitude Test), or both. Students in their junior year (5th form) can take the PSAT (Preliminary Scholastic Aptitude Test) as a practice run for the SAT.
We don’t have 1.1 or 2.1 or any of that stuff in the US like at the Oxbridge unis, but cum laude, magna cum laude and summa cum laude, as @dpworkin has said.