A quantitative metallographic method to measure pore sizes and pore distributions in cast aluminum components. An image of a location of interest in a cast component sample is first obtained using an image analyzer. Spacing criteria, such as a measure of the secondary dendrite arm spacing, may be used with the received image to provide evidence of pore clustering. This allows the system to performing calculations to determine if multiple pores can be clustered or grouped together as a single pore in three-dimensional space. From this, the total area of the pores in each of these groups or clusters is calculated and used as a representation of the pore area for that cluster. In general, pore size and pore distribution measurements in cast components achieved by the present invention show accurate predictions of pore size and spacing, and in particular evidence a reduced tendency to under-predict the size and distribution of actual pores.