PA28 Performance computes all the useful performance numbers for flight planning for Piper model PA28 Dakota, Archer, Warrior, and Cruiser aircraft. It includes calculations for takeoff, landing, climb, cruise, descent, instrument procedures as well as emergencies. It also includes an interactive hold calculator, a risk analysis tool, and an emergency glide distance calculator that handles head and tailwinds.
PA28 Performance is also available as a WebApp (an App that runs in a browser) that runs on a variety of platforms (PC, Mac, tablets, phones). The Cloud Sync feature allows flight planning profiles entered on any device to be synchronized with your other devices when connected.
PA28 Performance is a free, published-source development effort and has Apps and WebApps for other aircraft. See http://pohperformance.com for complete details.