The gameplay loop of Cookie Clicker is simple: amass cookies by clicking or passively, upgrade production abilities, watch cookie totals go up, and repeat. You start with a single cookie and a cursor that can click on it.
Each click produces one cookie. As your number of cookies increases, you can purchase upgrades and buildings that can produce more cookies automatically. Upgrades are located above the building purchase area and increase cookie clicker production and efficiency. Buildings are located below the upgrade area and range from grandmas who bake cookies to portals that summon cookies from another dimension. Each building has a base cost and a base production rate, which can be improved by upgrades.