A pedometer, or step-counter, is a device, usually portable and electronic or electromechanical, that counts each step a person takes by detecting the motion of the person's hands or 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 is desired, though there are now pedometers that use electronics and software to determine how a person's step varies automatically. Distance traveled can be measured directly by a GPS receiver.