Flat Iron vs Top Round Steak — What's the Difference?
Quick Answer
Flat Iron (flat iron steak) and Top Round Steak (top round steak) are not the same cut: Flat Iron is chuck primal (Infraspinatus muscle, top blade of the shoulder clod); Top Round Steak is round primal (Steak cut from the inside round / top round).
Canonical entities: Flat Iron · Top Round Steak
Side-by-side
| flat iron | top round steak | |
|---|---|---|
| Primal | chuck | round |
| Muscle / location | Infraspinatus muscle, top blade of the shoulder clod | Steak cut from the inside round / top round |
| Character | The second most tender muscle on the entire animal, after the tenderloin. A flat, rectangular steak extracted from the top blade by splitting it along the central connective tissue. Uniform thickness makes it ideal for grilling. Also known as butler's steak in the UK. | A lean, affordable steak cut from the inside round. Often marketed as 'London Broil' in US supermarkets, though London broil is technically a preparation method, not a cut. Best when marinated, grilled to medium-rare, and sliced very thin against the grain. Overcooking makes it tough and dry. |
Key differences
- Different primals: chuck vs round.
- Texture and slicing: compare fibrous, grain-heavy cuts vs more tender steak-style muscles based on each cut’s description.
- Retail naming diverges by country—always map through a canonical cut when translating menus or labels.
When to use each
Flat Iron
Pick Flat Iron when you want its specific marbling/texture profile: The second most tender muscle on the entire animal, after the tenderloin. A flat, rectangular steak extracted from the top blade by splitting it along the central connective tissue. Uniform thickness makes it ideal for grilling. Also known as butler's steak in the UK.
Top Round Steak
Pick Top Round Steak when its primal/muscle traits fit the dish: A lean, affordable steak cut from the inside round. Often marketed as 'London Broil' in US supermarkets, though London broil is technically a preparation method, not a cut. Best when marinated, grilled to medium-rare, and sliced very thin against the grain. Overcooking makes it tough and dry.
Flat Iron and Top Round Steak are different canonical muscles/primals: Flat Iron is chuck (Infraspinatus muscle, top blade of the shoulder clod); Top Round Steak is round (Steak cut from the inside round / top round).
Choose based on tenderness, marbling, grain direction, and how you plan to cook (sear vs braise vs slice thin).
Read the full guides: flat iron (what-is) · top round steak (what-is) · flat iron hub · top round steak hub