T-Bone vs Porterhouse — What's the Difference?
Thomas Joseph Butchery — The Cut Guide
T-Bone vs Porterhouse — What's the Difference?
Same bone. Same two muscles. One very specific difference — and it changes which steak you should buy. Here is the definitive answer, from the team at Thomas Joseph Butchery.
The T-bone and the porterhouse are the most frequently confused steaks on any menu — and understandably so. They look almost identical, they come from the same section of the animal, they both contain sirloin and fillet separated by the same T-shaped lumbar bone, and they are often listed at similar prices. But there is a single, meaningful difference between them that determines which one you are actually buying: the size of the fillet. Get that right and the choice between them becomes straightforward.
"Same bone. Same primal. Two cuts defined by a single measurement — how far back along the short loin the butcher's knife falls. That distance is the entire difference between a T-bone and a porterhouse."
The AnatomyWhere Both Cuts Come From
Both the T-bone and the porterhouse are cut from the short loin — the section of the animal that runs along the spine between the fore-rib and the round, behind the sirloin. At this point in the animal two muscles are present simultaneously on either side of the lumbar vertebra: the longissimus dorsi (the sirloin muscle, on the larger side) and the psoas major (the tenderloin or fillet, on the smaller side).
The short loin runs in one direction: from front to back. At the front end, where the tenderloin is just beginning to appear and is at its narrowest, cuts taken from this section have a small fillet portion. These are T-bones. As the butcher moves further back along the short loin toward the rear of the animal, the tenderloin broadens to its full width. Cuts taken from this section have a substantially larger fillet portion. These are porterhouses.
That is the entire anatomical distinction. Same primal, same two muscles, same bone — different position along the short loin, different size of fillet as a result.
Side by SideT-Bone & Porterhouse from Thomas Joseph Butchery
The Classic
T-Bone Steak
Grass-fed, dry-aged in-house at Coxtie Green Farm. Cut from the forward section of the short loin — sirloin-led, with a smaller fillet. The more manageable size makes it a serious individual steak.
32 Day / 750g — £33.75 | 45 Day / 750g — £37.50 Shop T-Bone →The Statement
Porterhouse Steak
Grass-fed, dry-aged in-house at Coxtie Green Farm. Cut from the rear of the short loin where the fillet is at its widest. Available at 1kg, 1.5kg and 2kg — a generous sharing steak with a substantial fillet section alongside the sirloin.
32 Day / 1kg — £52 | 45 Day / 1kg — £57 Shop Porterhouse →The DetailEvery Difference That Matters
| Factor | T-Bone | Porterhouse |
|---|---|---|
| Cut from | Forward section of the short loin — tenderloin tapering | Rear section of the short loin — tenderloin at full width |
| Fillet portion | Smaller — the tenderloin is still narrowing at this point | Substantially larger — the tenderloin is at its broadest |
| Sirloin proportion | Dominant — more sirloin than fillet | More balanced — fillet holds its own against the sirloin |
| Character | Sirloin-led: clean, bold, beefy — with a tenderness accent from the fillet | More balanced eating: sirloin depth alongside serious fillet tenderness |
| Typical weight | 750g at TJB | 1kg at TJB |
| Serves | 1 generously, or 2 with sides | 2 comfortably |
| Dry-ageing at TJB | 32-day and 45-day expressions | 32-day and 45-day expressions at 1kg, 1.5kg and 2kg |
| Price at TJB | From £33.75 | From £52 (32-day 1kg) |
| Best cooking method | Cast iron pan — bone upright first, then flat | Cast iron pan to oven — the extra thickness needs the oven finish |
| Temperature to pull | 54°C at the fillet side | 54°C at the fillet side |
The ChoiceWhich One Should You Buy?
You want bold sirloin character with fillet tenderness alongside it
The T-bone is the sirloin's best format. It delivers the clean, intensely beefy flavour of dry-aged sirloin with the butter-soft tenderness of the fillet in the same cut. At 750g it is a serious individual steak. At 32-day and 45-day aged expressions it is the more accessible entry point into the bone-in two-muscle experience. The right choice for most occasions.
The fillet is the priority and the occasion demands something more
The porterhouse is the T-bone taken to its logical conclusion — more fillet, more weight, more presence on the plate. At 1kg it is the natural sharing steak for two, available at 1.5kg and 2kg when feeding more. The right choice when the fillet portion matters as much as the sirloin and the occasion calls for something to carve at the table.
The CookHow to Cook Both Cuts
The cooking principle is identical for both — bone upright first, then flat on each side, measure the temperature at the fillet. The differences are in timing and the need for an oven finish on the heavier porterhouse.
🔥 The Rule That Applies to Both
Always stand it upright on the bone first. Neither face goes down into the pan first. Stand the steak on the bone for 2–3 minutes before laying it flat — this brings the bone to temperature and begins cooking both muscles simultaneously from the centre. It gives the thicker sirloin side a head start before the faster-cooking fillet side takes over when the faces hit the pan. Skipping this step is the single most common reason T-bones and porterhouses are cooked unevenly.
Always measure the temperature at the fillet side. The fillet is thinner, leaner and reaches 54°C faster than the sirloin. If you measure at the sirloin and pull at 54°C there, the fillet will already be at 58–60°C. The fillet is the more delicate and more expensive muscle in the cut — protect it accordingly.
T-Bone — Pan Only
At 750g the T-bone cooks entirely on the hob. Bone upright for 2–3 minutes, then 2 minutes flat on each side over maximum heat. Baste with butter, thyme and garlic for 60 seconds. Pull at 54°C measured at the fillet. Rest 6–8 minutes. Carve the sirloin and fillet separately off the bone before serving.
Porterhouse — Pan to Oven
At 1kg and 100-day aged, the porterhouse needs an oven finish. Same start: bone upright for 2–3 minutes, then 3 minutes flat on each side over maximum heat. Baste. Transfer the pan to a 200°C oven for 8–12 minutes until 54°C at the fillet. Rest for 10 minutes — non-negotiable at this weight. The bone retains heat and continues to cook both muscles gently during the rest, which is part of why the eating quality at this size is superior to attempting to cook it through on the hob alone.
Frequently Asked Questions
T-Bone vs Porterhouse — Your Questions Answered
What is the difference between a T-bone and a porterhouse?
The only difference is the size of the fillet portion. Both are cut from the short loin and contain sirloin and fillet separated by the T-shaped lumbar bone. A T-bone is cut from further forward along the short loin where the tenderloin is still tapering, producing a smaller fillet section. A porterhouse is cut from further back where the tenderloin is at its broadest, producing a substantially larger fillet section and a heavier, more balanced steak overall.
Is a porterhouse bigger than a T-bone?
Yes — in two respects. The porterhouse is cut from further back along the short loin where the tenderloin is at its widest, producing a larger fillet portion. And because the tenderloin adds more mass at this point, a porterhouse typically weighs more than a T-bone from the same animal. At TJB our T-bone is 750g and our porterhouse is 1kg.
Which is better — T-bone or porterhouse?
Neither is objectively better — it depends on what you prioritise. If you want the boldness of dry-aged sirloin to dominate and the fillet tenderness to accent it, the T-bone is the better choice. If you want the fillet to play an equal role alongside the sirloin — and you are sharing between two — the porterhouse is the right call. The porterhouse is not simply a larger T-bone; it is a fundamentally different eating experience because of how much fillet it contains.
How do you cook a T-bone or porterhouse steak?
The key technique for both is to stand the steak upright on the bone for 2–3 minutes before placing either face flat in the pan — this heats the bone and begins cooking both muscles simultaneously. Then sear flat for 2–3 minutes per side. The T-bone at 750g cooks entirely on the hob. The porterhouse at 1kg needs a further 8–12 minutes in a 200°C oven after the sear. For both, always measure the temperature at the fillet side — pull at 54°C for medium-rare — and rest for at least 6–10 minutes before carving.
How many people does a porterhouse steak serve?
At 1kg, a porterhouse serves two comfortably as a main course with sides. Carve the sirloin and fillet separately off the bone, slice each muscle and divide between two warm plates. Each person gets both the sirloin and fillet experience from the same steak.
Where can I buy T-bone and porterhouse steak in the UK?
Thomas Joseph Butchery stocks grass-fed, dry-aged T-bone at 32-day (£33.75) and 45-day (£37.50) expressions at 750g, and a grass-fed dry-aged porterhouse at 32-day and 45-day in 1kg, 1.5kg and 2kg from £52. Both sourced from cattle raised across British and Irish farms, dry-aged in-house at Coxtie Green Farm, cut fresh to order and delivered next day anywhere in the UK.
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