In UX/UI, the user base refers to the entire group of individuals who regularly use a digital application, website, or app. It includes both active users and occasional visitors and serves as a key metric for guiding design decisions. Understanding the user base allows designers to tailor products to the needs and expectations of actual users by analyzing demographic characteristics, behaviors, and preferences. A solid knowledge of the user base helps create user-centered designs that are not only functional but also engaging and efficient, ultimately enhancing user satisfaction and retention.