Strip loinThe larger piece of meat. Sold alone it is a strip steak.
TenderloinThe smaller piece of meat, also called the filet.
T-shaped boneHalf of a lumbar vertebra, a bone of the backbone.
MarblingFine flecks of fat within the lean meat.
Where it is cut 2
Short loinThe front part of the loin. Both steaks are cut from it.
T-bone steakThe same cut from nearer the front, with a narrower tenderloin.
How this list was compiled: Every name checked on 2026-10-01 and kept only where two independent sources use it. (1) USDA Agricultural Marketing Service, Institutional Meat Purchase Specifications, Fresh Beef, Series 100, https://www.ams.usda.gov/sites/default/files/media/IMPS_100_Fresh_Beef%5B1%5D.pdf (item 1173, porterhouse steak, and item 1174, T-bone steak: both prepared from the short loin, the tenderloin at least 1.25 inches wide on a porterhouse and at least half an inch on a T-bone, measured parallel to the back bone; item 173, short loin: the anterior section of the loin, with the sirloin removed behind it; item 1179, strip loin steak, bone-in; the tail measured from the longissimus dorsi). (2) Wikipedia, text only: T-bone steak, https://en.wikipedia.org/wiki/T-bone_steak (both steaks are cut from the short loin and include a T-shaped lumbar vertebra; the porterhouse comes from the rear end and has more tenderloin beside a large strip steak; the T-bone is cut closer to the front; the bone is a lumbar vertebra sawn in half; marbling). (3) Texas A&M University, Meat Science, Beef Loin Porterhouse Steak, https://meat.tamu.edu/meat-science/teaching/ansc-307-meats/beef-loin-porterhouse-steak/ (the muscles: psoas major, which is the tenderloin, and longissimus lumborum, which is the strip loin). (4) USDA Agricultural Marketing Service, Beef Grading Shields, https://www.ams.usda.gov/grades-standards/beef/shields-and-marbling-pictures (marbling: the amount of fat interspersed with lean meat). Licence: own work
The drawing: Drawn for this site on 2026-10-01 from plain geometry; nothing traced. The steer is the outline of this site's beef cuts drawing. Licence: own work
How it works
The parts of a porterhouse are two muscles and the bone between them: the strip loin on one side, the tenderloin on the other. The second drawing shows where the steak is cut, with a T-bone for comparison.
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The steak
Numbers 1 to 4 are on the porterhouse. The strip loin is the larger piece of meat and the tenderloin, or filet, the smaller. The T-shaped bone between them is half of a lumbar vertebra. Marbling is the fine fat inside the lean meat.
Where it is cut
Number 5 is the short loin, the front part of the loin, behind the ribs. Number 6 is a T-bone steak. Both steaks come from the short loin; the porterhouse is cut from its rear end, where the tenderloin is wider.
By the USDA specification a porterhouse has a tenderloin at least 1.25 inches wide; a T-bone, at least half an inch.
Questions and answers
What are the two sides of a porterhouse?
The strip loin and the tenderloin. The strip loin is the larger side; sold alone it is a strip steak. The tenderloin is the smaller side, also called the filet.
What is the difference between a porterhouse and a T-bone?
The width of the tenderloin. Both are cut from the short loin with the same T-shaped bone. A porterhouse comes from the rear end, where the tenderloin is wider; a T-bone is cut closer to the front.
What is the bone in a porterhouse?
Half of a lumbar vertebra, a bone of the lower back. The backbone is sawn down the middle, and the stem of the T is the part of the vertebra that points out to the side.
Where is the porterhouse on a cow?
In the short loin, the front part of the loin. It lies along the back, behind the ribs and ahead of the sirloin.