The lack of a percentile function in DAX is a commonly brought up challenge. In order to replicate a version that matches what the Excel Percentile.INC (inclusive) function does, you have to jump through a few hoops. This process involves having to create several measures to hold some intermediate values to apply a final formula. In theory, you could do it all in one DAX expression, but it would very difficult to read and test. Here's a step-by-step guide for replicating Excel percentile in DAX.