Aardvark Pedometer Free app for iPhone and iPad

Very accurate step counter. Lighter version of Aardvark Pedometer. Great charts.

Works on phones with or without built in step counters. Great easy to read charts show your steps per hour and steps per day. Use the step counter page to view your steps, distance, and current heart rate (if connected to a Bluetooth heart rate monitor). Reset to see how far it is from one place to another -- great to know how far it is from your car to a building or how many steps at work. Resetting does not affect your count for the day in the charts.
Integrated with Apple Health.

Other charts and features available in the paid version including: distance per hour, distance per day, step cadence (speed you walked broken down by minute), and additional heart rate data.

Continued use of GPS running in the background can dramatically decrease battery life.