A fitness center is a public or commercial facility for physical exercise, training, and athletic recreation. Fitness centers are usually membership-based commercial establishments, or public exercise facilities (often in parks). They normally include areas or equipment for weight training, running (e.g. on treadmills), swimming, aerobics, and other forms of exercise. There may also be courts for indoor sports like squash or basketball.

This usage does not include private exercise rooms for building tenants.

The facility supports general physical conditioning and may also contain courts or other recreational sports areas. A private exercise room for a building's tenants remains distinct from a public or commercial fitness center.