Kepler-640 is a Sun-like G-type star (about 1.01 solar masses, 5,653 K, 0.94 solar radii), 558 light-years from Earth. Kepler-640 b is a planet with 2.6 Earth radii, with an orbital period of 22.2 days, discovered in 2016 via transit. The planet was found when it crossed the face of its star, producing periodic dips in brightness that reveal its size and orbital period to space-based photometry. At roughly 558 light-years, Kepler-640 lies far beyond the nearest stars yet remains reachable to large survey telescopes.