What is the biggest planet in the universe?

As of 2015, the largest known planet in the universe is TrES-4, a gas giant that is approximately 1.7 times the diameter of Jupiter, but only approximately 92 percent as massive. Located 1,430 light-years from Earth, TrES-4 was discovered in 2007 in the Hercules constellation by the Trans-Atlantic Exoplanet Survey.

Scientists have speculated that there are other, larger gas giants besides TrES-4, with the biggest capable of achieving a size 15 times that of Jupiter. The TrES-4 system consists of the planet TrES-4, star TrES-4 A and star TrES-4 C. The presence of two stars in the system makes it a binary system.