One of the questions on the common app is whether the rank is weighted or unweighted. At my school, we have decile ranks shown on our transcripts on Aeries, and it says what our decile rank number is out of the size of our class, but how do we know whether it is weighted or unweighted?
Class ranks are usually based on weighted GPAs, as that takes into account course difficulties (AP/IB/Honors etc.) Check with your Guidance Counselor to be sure, however.
Ask someone who knows.