I think that question is rather abstract. You need to specify. There are other variables that are as important as your percentile, such as:

1) how many people were in your year? If you're top 5 percent but you graduated with only 50 in your year, that's really not as impressive as someone who made top 5 out of 500 people

2) what is your university's reputation? I assume that a lower reputed university would require a higher relative ranking

Ok, I'm really bad at math so could you explain 1) again? I mean being in the top 5% should be just as hard in a very large class as in a small one, or not? In the small class you have less competition but there are also less spots in the top 5%. In the large class you have more competition but also more spots in the top 5%....

I would see how it is harder to get a top 5 *rank* in a larger class, but not when we talk about percentage...

Can anyone explain this to me like I am 5? :-)

This is not about being bad at maths. Knowing how to calculate the % of X is pure general knowledge, like being able to say instantaneously the result of 12x12 or 9+1. Everyone knows (or should know) how much they stack up...

The formula is 5% x (the number of students in your class).

You're right. If there's a larger cohort, there's a larger group of students who graduate in top 5%, thus more intense competition. If there's a smaller one, it's vice-versa.

It's not about who's in the rank, I.e. you're the 4th best and I'm the 5th, and after me the rest doesn't matter.

Let's say you have 220 students in your class. 5%x220=11. So 11 people are in top 5%. Hope this helps.

Thanks for the explanation! So to be absolutely clear: The size of your class has no relation to the significance of being in the top 5%? Its just as good to be in the top 5% if you are in a big class as it is in a small class?