What’s the Difference Between a Porterhouse and a T-bone Steak?

The T-bone and porterhouse are steaks of beef cut from the short loin. Both steaks include a “T-shaped” bone with meat on each side. Porterhouse steaks are cut from the rear end of the short loin and thus include more tenderloin steak, along with (on the other side of the bone) a large strip steak. T-bone steaks are cut closer to the front, and contain a smaller section of tenderloin.

There is little agreement among experts on how large the tenderloin must be to differentiate a T-bone steak from porterhouse. The U.S. Department of Agriculture’s Institutional Meat Purchase Specifications state that the tenderloin of a porterhouse must be at least 1.25 inches (32 mm) thick at its widest, while that of a T-bone must be at least 0.5 inches (13 mm). However steaks with a large tenderloin are often called a “T-bone” in restaurants and steakhouses despite technically being porterhouse.