Methods and apparatuses for correcting an impedance measured by a sensor included in a wearable device are provided. In an exemplary embodiment, the methods includes: measuring, from an image including the wearable device and arms of a user, a first angle between a straight line connecting a left elbow joint of the user and a camera device for photographing the image and a straight line connecting the left elbow joint and the wearable device, a second angle between a straight line connecting the left elbow joint and the wearable device and a straight line connecting the wearable device and a right elbow joint of the user, a third angle between a straight line connecting the right elbow joint and the wearable device and a straight line connecting the right elbow joint and the camera device, and a fourth angle between a straight line connecting the right elbow joint and the camera device and a straight line connecting the left elbow joint and the camera device.