How does a 4 on an ap test impact your chances at an Ivy?

I took four APs this year:
AP Psych (5)
AP US History (5)
AP Calculus AB (5)
AP Bio (4)

Im working towards and ivy and was wondering how the 4 would effect my chances. Thanks!

Won’t make one iota of difference. Generally, one does not even report AP scores to universities until AFTER being admitted.

Better question to ask yourself: what school, specifically, are you interested in, and why. Treating “the ivies” as though they were interchangeable cogs suggests you haven’t really got much notion of what a higher education, there or elsewhere, is going to be like. Consider your actual goals.

It doesn’t.