Flap Steak vs Top Round Steak — What's the Difference?
Quick Answer
Flap Steak (flap steak (sirloin flap)) and Top Round Steak (top round steak) are not the same cut: Flap Steak is sirloin primal (Bottom sirloin, obliquus internus abdominis muscle); Top Round Steak is round primal (Steak cut from the inside round / top round).
Canonical entities: Flap Steak · Top Round Steak
Side-by-side
| flap steak | top round steak | |
|---|---|---|
| Primal | sirloin | round |
| Muscle / location | Bottom sirloin, obliquus internus abdominis muscle | Steak cut from the inside round / top round |
| Character | A thin, coarse-grained steak from the bottom sirloin. The American name for what the French call bavette d'aloyau. Open grain absorbs marinades extremely well. Popular for fajitas, stir-fry, and carne asada. Often confused with skirt steak but from a different location entirely. | 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: sirloin 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
Flap Steak
Pick Flap Steak when you want its specific marbling/texture profile: A thin, coarse-grained steak from the bottom sirloin. The American name for what the French call bavette d'aloyau. Open grain absorbs marinades extremely well. Popular for fajitas, stir-fry, and carne asada. Often confused with skirt steak but from a different location entirely.
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.
Flap Steak and Top Round Steak are different canonical muscles/primals: Flap Steak is sirloin (Bottom sirloin, obliquus internus abdominis muscle); 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: flap steak (what-is) · top round steak (what-is) · flap steak hub · top round steak hub