The most realistic answer is that a six-foot urban bench comfortably seats two to three adults. Three is usually the practical maximum if you want any real personal space.
A common planning standard for comfortable bench seating is about 24 inches of width per adult. Since six feet equals 72 inches, the math gives you three adults at 24 inches each. But real public bench space doesn’t always work like a calculation.
Strangers tend to leave a gap between themselves and the next person, often the width of one open seat. That means two people often occupy a six-foot urban bench comfortably in public, while three works better for friends, couples, or family members who don’t mind sitting closer. Four can squeeze in during a busy day, but that is no longer comfortable for most adults.
Urban bench dimensions and design change the answer too. A flat, backless bench feels more flexible because people can sit at slight angles or use the ends. A bench with armrests, a center divider, or thick supports reduces usable width and can make three adults feel tight. Bags, coats, body size, and how people sit all affect the real-world bench seating capacity.
So for planning or everyday curiosity, think of a six-foot urban bench as a two-to-three-person bench: two people when they are strangers, and three people when they are okay sitting shoulder to shoulder.