A pedometer is a device, usually portable and electronic or electromechanical, that counts each step a person takes by detecting the motion of the person's hips. Because the distance of each person's step varies, an informal calibration, performed by the user, is required if presentation of the distance covered in a unit of length (such as in kilometres or miles) is desired.

Used originally by sports and physical fitness enthusiasts, pedometers are now becoming popular as an everyday exercise measurer and motivator. Often worn on the belt and kept on all day, it can record how many steps the wearer has walked that day, and thus the kilometres or miles (distance = number of steps × step length). Some pedometers will also erroneously record movements other than walking, such as bending to tie one's shoes, or road bumps incurred while riding a vehicle, though the most advanced devices record fewer of these 'false steps'. Step counters can give encouragement to compete with oneself in getting fit and losing weight. A total of 10,000 steps per day, equivalent to 5 miles (8.0 km), is recommended by some to be the benchmark for an active lifestyle, although this point is debated among experts. Step counters are being integrated into an increasing number of portable consumer electronic devices such as music players and mobile phones.