Wii Fit requires the use of the Wii Balance Board, a unique platform peripheral that the player stands upon during play. The Wii Balance Board can detect and track the user's center of balance (COB),a feature heavily utilized in the game; it will also measure weight in the same way as a bathroom scale. Wii Fit contains more than 40 activities designed to engage the player in physical exercise, which consist of yoga poses, strength training, aerobics, and balance games.  Most activities generally focus on maintaining COB and improving posture.
Players register and play in Wii Fit via a user profile, assigned with the player's date of birth, height, and Mii character, that keeps track of the player's progress. Physical activities done outside of Wii Fit can also be logged into the profile. Wii Fit allows up to eight different profiles to be registered.