Monitor your day with the Fitbit One - this tracker aims to empower and encourage you by delivering real-time feedback that helps you be more active. Why not take the stairs instead of the elevator? Or go for a quick walk after lunch? Those steps will add up fast. One tracks steps taken, stairs climbed, distance travelled, calories burned, hours slept and quality of sleep. Powered by Fitbit's leading-edge accelerometer and altimeter, the One accurately captures all-day activity that old-school pedometers can't handle. It bases calculations like calories burned on your personal profile - reflecting your stats.