Ok I'll try to explain the difference.
T-Bone Versus Porterhouse Steaks
T-Bone steaks and Porterhouse steaks are the same. The Porterhouse is just a larger version of the T-Bone because it is carved from the larger portion of the tenderloin. A Porterhouse is the "King of the T-Bones".
Diagram Showing Beef Cuts Both are cut from the short loin area of the beef. A center "T-Shaped Bone" divides two sides of the steak. On one side is a tenderloin filet and the other is a top loin which is better known as the New York Strip Steak.
When the bone is removed, the result is two distinctly different steaks. A Filet and a New York Strip. When the bone is left on either side, it becomes either a "Bone-in Filet" or a "Bone-in New York Strip".
The Porterhouse is much larger and is sometimes served for two. The USDA specifications require the filet portion must be at least 1.25" thick at its widest point to qualify labeling as a Porterhouse Steak. A T-Bone Steak must be at least 0.25" thick. Any smaller, it would be called a Club Steak. The next time you try to decide between a T-Bone or Porterhouse, remember that size is the only difference.
When you order a T-Bone or Porterhouse, it's like doubling your dining delight. Particularly when dining on Certified USDA Prime. If you order a 24-ounce Porterhouse, hope you're hungry.