The hdpw (head-in-a-pumping-well) program described in this report is a post-processor that calculates the head in a pumping well based on thesimulated head at a finite-difference model cell that contains the well. The calculations are based on the Thiem equation. The hdpw code works with the U.S. Geological Survey modular finite-difference ground-water flow model, which is commonly called MODFLOW. The hdpw code is a complete program that has incorporated many of MODFLOW subroutines to read data. Code was added to the well package to calculate the head and drawdown in a fully-penetrating well of finite radius.