What is the largest planet ever discovered?
It is 13 times the size of Jupiter and 2.5 times the mass of the Sun.
"astronomers have spotted a planet 13 times more massive than Jupiter, the largest planet in our own solar system.
The planet orbits a star called Kappa Andromedae that is 2.5 times the mass of the sun and is located 170 light-years away from Earth. As a gas giant larger than Jupiter, it's classified as a "super-Jupiter."" - https://www.scientificamerican.com/article/super-jupiter-discovery-d/