Interval Runner is a mobile phone application for runners that use Interval Methods. Interval Methods consist of alternating Run and Walk periods and have shown to improve runner performance. Before the workout, the runner sets these periods (for example, 2 minutes running, 1 minute walking) in Interval Runner and then,during workout listens to announcements of when to walk or run. The runner also has the option of hearing periodic reports on speed, distance and comparison to a goal. After the workout, the runner can review their performance on a minutes-by-minutes, miles-by-mile, or interval-by-interval basis using a Google Map or an embedded table. And, your workout can be share on Facebook and other social media. Interval Runner needs only your mobile phone and works in both foreground and background with music playing. It does not contain advertising or need a web site. Many features of Interval Runner can be customized including voice, language, spoken statements, maps and others. A free demo is available at www.intervalrunner.com . Continued use of GPS running in the background can dramatically decrease battery life.