Hit Factor Calculator for IPSC and USPSA shows you Hit Factor for the stage given information from your scoresheet -- time, all hits and penalties.
Unique features of this app are a "What If..." tab which quickly shows you the possible Hit Factor without penalties and a "Dream Score" tab which allows you to play with any values of the scoresheet and compare result with your actual Hit Factor.
This is a completely free app, without ads or in-app purchases.