Flap Steak vs Sirloin Tip — What's the Difference?
Quick Answer
Flap Steak (flap steak (sirloin flap)) and Sirloin Tip (sirloin tip (knuckle)) are not the same cut: Flap Steak is sirloin primal (Bottom sirloin, obliquus internus abdominis muscle); Sirloin Tip is round primal (Front of the rear leg, between sirloin and round).
Canonical entities: Flap Steak · Sirloin Tip
Side-by-side
| flap steak | sirloin tip | |
|---|---|---|
| Primal | sirloin | round |
| Muscle / location | Bottom sirloin, obliquus internus abdominis muscle | Front of the rear leg, between sirloin and 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. | Also called the knuckle. A lean, moderately tender cut from the front of the round, near the sirloin. Used for roasts, kabobs, and stir-fry. Not from the sirloin despite the name. |
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.
Sirloin Tip
Pick Sirloin Tip when its primal/muscle traits fit the dish: Also called the knuckle. A lean, moderately tender cut from the front of the round, near the sirloin. Used for roasts, kabobs, and stir-fry. Not from the sirloin despite the name.
Flap Steak and Sirloin Tip are different canonical muscles/primals: Flap Steak is sirloin (Bottom sirloin, obliquus internus abdominis muscle); Sirloin Tip is round (Front of the rear leg, between sirloin and 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) · sirloin tip (what-is) · flap steak hub · sirloin tip hub