Flank Steak vs Skirt Steak: A Butcher Breaks Down the Real Differences

Two Cuts, One Constant Mix-Up

If I had a dollar for every time someone asked me for "that flat steak for fajitas" and couldn't tell me whether they meant flank or skirt, I'd have retired ten years ago. These two cuts get swapped, confused, and mislabeled more than any other pair in the butcher case.

And I get it. They're both long, flat, relatively thin steaks. They both take well to marinades. They both need to be sliced against the grain. On the surface, they look like the same category of meat.

But after 40 years behind the counter, I can tell you they're fundamentally different cuts with different textures, different fat content, different price points, and different ideal uses. Choose wrong, and you'll wonder why your fajitas aren't as good as the restaurant's. Choose right, and you'll understand why professionals obsess over the distinction.

Where They Come From: Anatomy Matters

Flank Steak

The flank steak comes from the abdominal muscles of the steer — the area below the loin and behind the plate. It's the rectus abdominis and obliquus internus abdominis muscles, essentially the cow's "abs."

Because this muscle helps support the animal's body cavity, it's a working muscle but not a heavily exercised one. The result is a lean, flat piece of meat with long, clearly visible muscle fibers running in one direction. A whole flank steak typically weighs 1.5 to 2.5 pounds and measures about 12 inches long by 6 inches wide, roughly three-quarters to one inch thick.

Skirt Steak

The skirt steak is the diaphragm muscle — the thin sheet of muscle that separates the chest cavity from the abdomen. There are actually two skirt steaks per animal:

• Outside skirt (diaphragm, costal portion): Thicker, more tender, better marbled. This is the premium one. Most outside skirt gets bought by restaurants or exported, which is why you rarely see it at retail.
• Inside skirt (diaphragm, crural portion): Thinner, tougher, less marbled. This is what you'll usually find at the grocery store when a package says "skirt steak."

A full skirt steak is long and narrow — sometimes 20 to 24 inches — and about half an inch to three-quarters of an inch thick. The grain runs across the width of the steak rather than lengthwise, which is an important detail when it comes time to slice.

Appearance: How to Tell Them Apart

Once you know what to look for, you'll never confuse them again:

Flank steak is wider and thicker, with a relatively smooth surface. The muscle fibers are tight and compact, running lengthwise along the steak. It looks like a solid, dense piece of meat — almost like a thick book.

Skirt steak is longer, narrower, and has a much more pronounced, almost "shaggy" grain pattern. The fibers are coarser and more loosely packed. You can see deep grooves between the muscle fibers. It also has significantly more visible fat within and around the muscle fibers.

If you pick up both raw and set them side by side, the difference is obvious: flank is compact and uniform; skirt is looser, more textured, and fattier.

Flavor and Texture: The Real Differences

Flank Steak: Clean and Beefy

Flank steak has an intense, direct beef flavor. Because it's lean (about 8-10% fat), the flavor is "clean" — pure beef without a lot of richness or butteriness. The texture when properly cooked and sliced is firm but tender, with a satisfying chew that's not tough. Think of it as the athletic steak — lean, muscular, no nonsense.

When sliced thin against the grain, a well-cooked flank steak has a texture similar to a good London broil (which, incidentally, is a cooking method traditionally applied to flank steak). It absorbs marinades well because the tight grain acts like a sponge.

Skirt Steak: Rich and Robust

Skirt steak is significantly fattier — especially the outside skirt, which can have marbling rivaling a ribeye. That fat content translates to a richer, more robust flavor. It's beefier than flank, with an almost buttery quality when cooked over high heat.

The texture is looser and more open-grained. When you bite into properly cooked skirt steak, the fibers separate almost effortlessly. It has a juicier mouthfeel because of that intramuscular fat. But overcook it and that loose grain becomes chewy and stringy in a way that flank doesn't.

Head-to-Head Comparison

Attribute	Flank Steak	Skirt Steak
Fat content	Low (8-10%)	Moderate-high (12-15%+)
Flavor intensity	Strong, clean beef	Rich, robust, buttery
Texture	Firm, compact grain	Loose, open grain
Tenderness	Moderate (when sliced correctly)	Higher (outside skirt)
Thickness	¾ to 1 inch	½ to ¾ inch
Weight (typical)	1.5–2.5 lbs	1–1.5 lbs per piece
Best temp	Medium-rare to medium	Medium-rare (max)
Marinade absorption	Excellent	Good

Price: What You'll Pay

Here's where the story has changed dramatically over the past decade. Both cuts used to be budget-friendly — the kind of thing working families bought for weeknight tacos. Popularity changed that.

Flank steak: $10–$14/lb for USDA Choice. It's become a victim of its own versatility — everyone wants it for everything from fajitas to stir-fry to stuffed braciole.

Skirt steak (inside): $10–$16/lb for Choice. The inside skirt is what you'll find at most grocery stores.

Skirt steak (outside): $14–$20/lb when available at retail. Restaurants and export markets drive prices up. If your butcher has outside skirt, buy it — it's worth every penny.

For a practical comparison: if you're feeding six people fajitas, you'll spend about $25–$35 for flank or $25–$40 for inside skirt. Both are reasonable for the quality you get.

Best Cooking Methods

Flank Steak

Grill (best): High heat, 4–5 minutes per side for medium-rare on a ¾-inch steak. The dense grain develops an excellent crust. Let it rest at least 5 minutes before slicing.

Pan sear: Screaming hot cast iron with a neutral oil. 3–4 minutes per side. Don't crowd the pan — if moisture builds up, you're steaming, not searing.

Broiler: 4 inches from the element, 5–6 minutes per side. The old-school "London broil" method works beautifully.

Marinate or not? Flank takes well to marinades because of its tight grain, but a quality Choice flank steak seasoned with just salt and pepper is excellent. If you do marinate, 2–4 hours is the sweet spot. Acid-based marinades (lime, vinegar) longer than 8 hours will turn the surface mushy.

Stir-fry: Slice flank thin against the grain before cooking, and it's one of the best stir-fry proteins you can use. Restaurant-quality results at home.

Skirt Steak

Grill (best): The hottest fire you can make. Skirt steak is thin, so it needs maximum heat for minimum time — 2–3 minutes per side. You want a charred exterior with a pink center. If your grill isn't screaming hot, the skirt will overcook before it develops a crust.

Cast iron: Same principle — ripping hot, 2 minutes per side. Open a window first. Skirt steak in a screaming cast iron produces serious smoke. The fat renders, the crust develops, and you get restaurant-quality carne asada in under 5 minutes.

Marinate or not? Traditional Mexican and Tex-Mex preparations almost always marinate skirt steak — citrus, garlic, cumin, chili. The open grain absorbs flavors well. But high-quality outside skirt with just coarse salt is extraordinary. Don't overthink it.

Critical note: Skirt steak must be served medium-rare at most. The open grain structure means that at medium and beyond, the fibers contract and tighten dramatically, turning a juicy cut into something resembling shoe leather. There's no recovering from overcooked skirt steak.

The Grain Rule: Don't Skip This

Both cuts absolutely must be sliced against the grain. This is non-negotiable. But here's where people mess up — the grain runs differently in each cut.

Flank steak: The grain runs lengthwise (parallel to the long side). So you slice perpendicular to the long edge — making your cuts across the width of the steak.

Skirt steak: The grain runs across the width (perpendicular to the long side). So you slice parallel to the long edge — or more practically, cut the long strip into 4–6 inch sections first, then slice each section against the grain.

Get this wrong and even a perfectly cooked steak will be tough and stringy. Get it right and both cuts are remarkably tender. I've seen grown adults cut with the grain, struggle through a chewy meal, and declare the steak "bad quality." The steak was fine. The knife work wasn't.

Which Cut Wins for Specific Dishes?

Fajitas: Skirt Steak Wins

Authentic Tex-Mex fajitas were invented using skirt steak — specifically, the outside skirt. The loose grain picks up charred, smoky flavors from a blazing-hot grill, and the higher fat content keeps it juicy even when sliced thin and held warm on a sizzling platter. If you've ever wondered why restaurant fajitas taste different from the ones you make at home, the answer is often "they're using outside skirt and you're using flank."

That said, flank makes perfectly good fajitas if skirt isn't available. It's just a leaner, more structured bite.

Carne Asada: Skirt Steak Wins

For the same reasons as fajitas — the char, the fat, the loose grain that soaks up salsa and guacamole. Skirt steak over mesquite charcoal, sliced and piled into warm corn tortillas, is one of the great simple meals in the world.

Stir-Fry: Flank Steak Wins

Flank's compact grain and lean profile make it ideal for stir-fry. Slice thin against the grain, toss in a screaming-hot wok with oil, and it sears quickly without releasing too much fat into the dish. The lean, clean flavor also pairs better with Asian sauces and aromatics. Chinese restaurants have been using flank for stir-fry forever — and they know what they're doing.

London Broil: Flank Steak Wins

The classic London broil method — broil or grill a whole flank steak, rest, slice thin — showcases flank's strengths perfectly. The uniform thickness ensures even cooking, the dense grain develops a great crust, and sliced thin it's tender and clean-tasting.

Stuffed and Rolled (Braciole, Matambre): Flank Steak Wins

Flank's uniform shape and dense texture make it ideal for stuffing, rolling, and braising or roasting. It holds its shape, doesn't fall apart, and the long fibers create a beautiful spiral when sliced. Italian braciole and Argentine matambre both traditionally use flank.

Tacos (General): Tie

Both work brilliantly for tacos. Skirt gives a richer, more indulgent bite. Flank gives a leaner, beefier bite. Both are excellent with cilantro, onion, and a squeeze of lime. Pick based on your mood and your budget.

Inside Skirt vs Outside Skirt: The Hidden Quality Gap

This distinction is worth its own section because most home cooks don't know it exists, and it dramatically affects the eating experience.

Outside skirt is the diaphragm's costal (rib-side) portion. It's thicker (¾ inch), wider, more marbled, and more tender. It's also covered with a membrane that needs to be removed — good butchers do this, grocery stores sometimes don't. Outside skirt is what restaurants use for fajitas, and it's why their version tastes better than yours.

Inside skirt is the crural (abdominal-side) portion. It's thinner (½ inch), narrower, leaner, and tougher. It also tends to have more sinew. This is what most grocery stores sell as "skirt steak."

If you see "skirt steak" at the store without an inside/outside designation, it's almost certainly inside. To find outside skirt, you'll need a quality butcher shop, a Latin market, or a good online source. It's worth seeking out.

Pro Tips from 40 Years of Cutting

1. Always bring to room temperature. These thin cuts cook fast. If the center is fridge-cold, you'll overcook the outside before the middle catches up. Pull them 30–45 minutes before cooking.
2. Salt early or at the last second. Salt 40+ minutes ahead (so moisture reabsorbs) or right before cooking. Salting 5–15 minutes before draws moisture to the surface at the worst possible time — right when you need a dry exterior for searing.
3. Rest before slicing. Five minutes minimum for either cut. This lets the juices redistribute. Cut immediately and they run all over your cutting board instead of staying in the meat.
4. Slice thin. Quarter-inch slices or thinner, against the grain. The thinner you slice, the more tender the eating experience. This isn't a ribeye where thick slices work — these are lean, long-fibered cuts that need thin slicing.
5. Save the juices. Both cuts release flavorful juices when resting and slicing. Pour them over the sliced meat or use them in your taco/fajita sauce. That's concentrated beef flavor — don't waste it.
6. Leftover hack: Cold sliced flank or skirt steak makes outstanding steak salads, sandwiches, and Thai beef salad (yam neua) the next day. The flavors actually intensify overnight in the fridge.

The Bottom Line

If you walk away from this guide remembering three things, make it these:

1. Skirt steak is fattier and more flavorful. Choose it for fajitas, carne asada, and dishes where char and richness matter.
2. Flank steak is leaner and more versatile. Choose it for stir-fry, London broil, stuffed preparations, and any recipe where you want clean beef flavor.
3. Always slice against the grain, always slice thin. This rule overrides everything else. Get the slicing right and both cuts are excellent. Get it wrong and neither one will impress you.

Both are honest, hard-working cuts that reward technique over expense. You don't need a $50 ribeye to eat well — you need a $12 flank steak, a hot grill, and the knowledge to handle it right.

For premium flank and skirt steak — properly trimmed and graded — browse The Meatery's steak collection for cuts sourced with the same care any good butcher would demand.