Is London Broil The Same As Flank Steak? | Cut Matchup Clear

No—these cuts come from different muscles, so they cook and slice a bit differently.

“London broil” and “flank steak” get mixed up all the time. They can look similar in the case, they both like bold seasoning, and they both taste great sliced thin.

Still, they aren’t the same thing. One name points to a specific cut. The other name is often a store label that hints at how the meat should be cooked and served.

Is London Broil The Same As Flank Steak? What The Name Tells You

Flank steak is a defined cut from one area of the cow. It’s long, flat, lean, and it has a strong grain that’s easy to see. When you cook it hot and slice it thin across the grain, it eats tender with a nice chew.

London broil is most often a retail label for a thick, lean steak meant to be marinated, cooked fast over high heat, then sliced thin. Many stores sell top round or bottom round as “London broil.” Some stores also use flank steak for the same style of meal.

If you want to see how labels treat this term, the USDA FSIS labeling policy book includes examples that pair “London broil” with a cut name as a style statement on a label.

London Broil Vs Flank Steak: The Simple Rule

If you want fewer surprises at dinner, start here: flank steak is the cut; London broil is often the plan. When a package says “London broil,” look for smaller text that tells you the actual cut (top round, bottom round, flank, sirloin, and so on).

Once you know what you’re holding, the rest gets easier. You pick a method that fits the thickness, season in a way that suits the muscle, then slice it so it eats well.

Why “London Broil” Shows Up On So Many Different Cuts

Grocery stores use “London broil” like a friendly shortcut. It signals “lean beef for marinating, broiling or grilling, then slicing thin.” It’s not a single muscle the way flank steak is.

That’s why you might buy “London broil” one week and get a thick piece of round, then buy it again later and get flank steak or another lean steak. The name is steering you toward a serving style, not a strict anatomy lesson.

When you want standard cut definitions that the meat trade uses, the USDA AMS IMPS 100 fresh beef specifications lays out how beef cuts are categorized and described.

Where Each One Comes From On The Cow

Location matters because it predicts texture. Muscles that work more end up leaner with longer fibers. That doesn’t make them bad. It means they need the right cook and the right slice.

Flank Steak Location And Structure

Flank steak comes from the flank area along the lower belly. It’s usually thinner than a typical “London broil” steak, and it’s wide and flat. The grain runs strongly in one direction, which is why slicing direction matters so much.

Flank steak shines with quick, high heat cooking. Grill it, broil it, or sear it hot. If you want slow cooking, flank can still work, but it needs enough time in liquid heat to fully soften.

London Broil Cuts: Common Options

When “London broil” is a thick round cut, it’s often top round or bottom round. These are lean muscles with tight fibers. They can feel firm if they’re cooked too far or sliced too thick.

Some stores use flank steak under the “London broil” label too, which is why reading the fine print helps. If you see “flank” on the label, you’re still getting flank steak.

Texture And Flavor: What Changes On The Plate

Both can taste beefy and satisfying. The eating experience changes with muscle type and thickness.

How Flank Steak Feels When You Eat It

Flank steak has a looser grain. Cook it to medium-rare or medium, then slice thin across the grain, and it’s tender with a pleasant chew. Slice with the grain and it can feel ropey.

Because it’s lean and flat, flank steak takes on marinades quickly. It’s a natural fit for fajitas, tacos, stir-fries, steak salads, and rice bowls.

How A London Broil Steak Feels When You Eat It

A thick “London broil” steak from the round is lean and can be firm. Its best version is a browned exterior with a pink center, followed by thin slices across the grain.

Cook that thick steak to well-done and it often turns dry and stiff. Keep it in the medium-rare to medium range, rest it well, and slice it thin. That’s the difference between “pretty good” and “why is this so chewy?”

How To Shop So You Get The Cut You Expect

Labels can be vague. A few quick checks keep you from buying the wrong thing.

Check The Secondary Cut Name

Many packages list the exact cut in smaller print. If you see “top round,” “bottom round,” or “round steak,” you’re looking at round being sold under the London broil label. If you see “flank steak,” it’s flank steak, even if “London broil” appears as a serving style note.

Use Shape And Thickness As A Clue

Flank steak is usually long and flat, often under an inch thick across most of the piece. Round cuts sold as London broil are often thicker and more rectangular, like a small roast sliced into a steak.

Ask One Direct Question At The Counter

“What cut is this?” gets a straight answer fast. If you’re ordering online, check the product description for the cut name, not just the marketing label.

Marinade And Seasoning: What Works Better For Each Cut

Both cuts do well with bold flavor. The trick is matching the method to the muscle so you get taste without turning the surface mushy.

Flank Steak Marinade Tips

Flank steak is thin, so it absorbs flavor quickly. A 2–8 hour marinade window is often enough. If your marinade leans hard on vinegar or citrus, keep it on the shorter side so the surface doesn’t turn pasty.

Flank steak plays well with soy sauce, garlic, onion, chili, cumin, black pepper, and a touch of sweetness. A little oil helps browning and carries fat-soluble flavors.

London Broil Marinade Tips

Thicker round cuts benefit from more time. An overnight soak can help flavor move in deeper, especially if you score the surface lightly in a shallow crosshatch. Keep the cuts shallow so you don’t tear the meat.

If you use a tenderizing trick like a pinch of baking soda, use a light hand. Too much can make the surface taste off. After marinating, wipe or lightly rinse excess marinade, then pat the steak dry so it browns well.

Table: London Broil And Flank Steak Compared

This table helps you choose based on what you’re cooking, not just what the front label says.

What You’re Buying	Typical Traits	Good Fits
Flank Steak (true flank cut)	Long, flat, strong grain, lean, cooks fast	Grill, broil, stir-fry, fajitas, steak salads
London Broil Labeled Top Round	Thick, very lean, tight grain, can be firm	Marinate, broil or grill, slice thin for platters
London Broil Labeled Bottom Round	Lean, a bit more connective tissue, hearty chew	Marinate, broil, slice thin; also works for braise
London Broil Labeled Flank Steak	Flank steak sold with a serving-style label	Same as flank; thin slicing is the win
Thickness Under 1 inch	Short cook window, browns fast, easy to overcook	Hot grill, quick broil, quick pan sear
Thickness 1–2 inches	More time for crust, needs temp control	Grill with two-zone heat, broil with distance
Strong Visible Grain	Chew depends on slicing direction	Slice thin across grain; bias slices help
Very Lean With Little Marbling	Can dry out if cooked too far	Medium-rare to medium; slice thin; serve with sauce

Cooking Methods That Fit Each Cut

When people say “London broil,” they often mean “cook it hot, keep it pink, slice it thin.” That approach can work for flank steak and for round cuts, but the details change with thickness.

Grilling Flank Steak

Pat the surface dry so it browns instead of steaming. Preheat the grill to high. Cook flank steak fast, flipping once, until the thickest part hits your target temperature.

Rest it, then slice thin across the grain on a diagonal. If the grain is hard to spot after cooking, look at the side edge and follow the lines.

Broiling Or Grilling A London Broil Steak

For a thick London broil steak, start with strong heat, then manage it so the outside doesn’t scorch before the center warms. A simple move is to sear over high heat, then finish on a cooler zone of the grill.

An instant-read thermometer takes the guesswork out. Pull the steak a bit early, rest it well, then slice as thin as you can across the grain. Thin slices aren’t decoration here—they’re the serving method.

Skillet Sear With An Oven Finish

When you can’t grill, a heavy skillet plus oven finish works nicely. Sear until you get color, then move the pan to a hot oven to finish. This suits thicker London broil cuts, and it can work for flank steak if the piece fits.

Slow Cooking: When You Want A Different Result

Flank steak can be braised for shredded beef dishes. Round cuts sold as London broil also do well in a braise when you want fall-apart texture. In that mode, you’re no longer chasing medium-rare slices—you’re cooking until the connective tissue softens.

Slicing Is The Make-Or-Break Step

You can nail the marinade and the temperature, then lose tenderness with one wrong cut of the knife. The fix is quick.

Spot The Grain Before Cooking

On flank steak, the grain is usually easy to see. Take a moment and note the direction. If you want, make one small notch on the edge so you can find it later.

Slice Thin Across The Grain

Use a sharp knife and cut across the fibers, not along them. Cutting on a diagonal gives wider slices while staying thin. On round cuts, the grain can be tighter and less obvious, so check the surface lines and the side edge.

Portion After Slicing

If you need shorter pieces for tacos or salads, slice across the grain first, then cut the long slices into bite-size pieces. Doing it in the other order makes it easier to cut with the grain by mistake.

Table: Doneness And Timing Cheatsheet For Thin Slices

These targets help you land a tender bite. Use a thermometer when you can, since thickness and heat level change timing fast.

Goal	Pull Temperature	Rest And Serve
Medium-rare slices	125–130°F	Rest 8–10 minutes, then slice thin across grain
Medium slices	135–140°F	Rest 10 minutes; slice thin; add a pan sauce
Extra-thin sandwich slices	125–135°F	Chill 20 minutes after resting, then slice very thin
Stir-fry strips	Rare to medium-rare	Slice thin first, then flash cook in a hot pan
Braised shred	Cook until tender	Simmer until it pulls apart; slicing isn’t the goal

Substitutions That Work When The Store Is Out

Sometimes flank steak is gone, or the only “London broil” left is a thick round cut. You can still get a great meal if you swap with a plan.

If You Wanted Flank Steak

Skirt steak is the closest feel: thin, beefy, and built for high heat and thin slicing. Flat iron steak is thicker and often more tender, so watch cook time and slice it the same way. If you choose a round cut, plan on a longer marinade and thinner slices.

If You Wanted A Thick London Broil Steak

Top sirloin can give you a similar “slice and serve” result with a softer bite. Tri-tip can also scratch the same itch, though its grain changes direction, so you’ll want to rotate the roast as you slice.

Common Mistakes That Make Either One Seem Tough

A tough bite usually comes from one of three issues: overcooking, thick slices, or cutting with the grain. Fix those and dinner gets a lot better.

Cooking Too Far Past Medium

Lean cuts don’t have much fat to buffer heat. Once they pass medium, they lose moisture fast. Pull early enough for carryover heat during the rest.

Skipping The Rest

Resting lets juices settle back into the meat. Slice right away and the board floods, and the slices taste drier even if you cooked them well.

Letting A Strong Acid Marinade Sit Too Long

Acid can soften the surface, then turn it grainy if it sits too long. If you want a long soak, lean on salt, aromatics, and a little sweetness, and keep the acid light.

Which One Should You Buy For Your Meal?

Choose flank steak when you want a thinner cut that cooks fast and works well in tacos, salads, and stir-fries. If you’re cooking for a crowd and want a platter of thin slices, a thick “London broil” steak from the round can be a smart pick—just plan on marinating and slicing thin.

Either way, your winning routine stays the same: cook hot, keep the center pink, rest the steak, then slice thin across the grain. If you want a quick cut reference for cooking methods and handling, the Beef. It’s What’s For Dinner flank steak page sums up common approaches and slicing notes in plain terms.