What is the top speed a car can go?

There's no single answer to the top speed a car can go. It depends entirely on the car's design, engine, aerodynamics, and even things like tire type and weather conditions.

While some purpose-built vehicles have exceeded 800 mph (like the Thrust SSC, which is a jet car, not a typical road car), the top speed of production road cars is considerably lower, typically in the range of 200-250 mph. Even then, achieving those speeds requires ideal conditions and specialized tracks.