Calculating Kinetic Energy?

So I want to find the kinetic energy and potential energy at any given point. I'm doing a projectile motion experiment. I know that the energy is conserved therefore whatever kinetic energy is lost is the amount of potential energy gained. My question is, is the kinetic energy calculated using the vertical velocity or the (total) velocity [both horizontal and vertical together] because doesn't potential energy concern with only vertical motion or am I wrong? Not sure; that's why I came here.