Halibut vs Flounder: Taste, Size, Price & Which to Cook

Halibut vs flounder is a size story: halibut is the largest flatfish in the ocean (NOAA lists Pacific halibut at up to 8 feet and 500 pounds) and is sold as thick, firm, mildly sweet steaks and fillets, while flounder is a 1- to 5-pound fish with thin, delicate, fine-flaked fillets. Halibut is technically part of the flounder group, but at the counter they are different products: halibut costs several times more and is built for grilling and roasting; flounder is for pan-frying, stuffing and baking.

Order halibut when you want a meaty, steak-like piece of fish that holds together on a grill; order flounder when you want something light, tender and quick, or when price matters more than thickness.

Halibut vs flounder at a glance

	Halibut	Flounder
Taxonomy	Pacific halibut, Hippoglossus stenolepis, family Pleuronectidae (right-eyed flounders)	Summer flounder (fluke), Paralichthys dentatus, Paralichthyidae (left-eyed); winter flounder, Pleuronectidae (right-eyed); Gulf and southern flounder in Florida
Where it lives	North Pacific from Santa Barbara to Nome, most common in the central Gulf of Alaska	Atlantic and Gulf coasts; summer flounder from Nova Scotia to east Florida; Gulf flounder on every Florida coast
Size	Up to 8 ft and 500 lb; lives up to 55 years	Summer flounder to about 3 ft; most table fish 1–5 lb; a 14-inch southern flounder weighs about 1.1 lb
Flavor	“Very mild and sweet” (NOAA)	“Delicate flavor” (NOAA); “mild flavor, lean fish” (FDACS)
Texture	“Flaky, tender, and firm”; large flakes, snow white when cooked	“Flaky and fine”; thin fillets with a delicate flake
Price	Varies; among the priciest white fish; 2024 dock value about $3.90/lb (NOAA)	Varies; far cheaper; winter flounder 2024 dock value about $1.95/lb (NOAA)
Best cooking methods	Grill, roast, sear or poach thick portions	Pan-fry, sauté, broil, bake, stuff whole
Nutrition, per 100 g raw (USDA)	91 kcal, 18.6 g protein, 1.33 g fat, 0.19 g EPA+DHA, 68 mg sodium	70 kcal, 12.4 g protein, 1.93 g fat, 0.25 g EPA+DHA, 296 mg sodium
Mercury (FDA)	“Good Choice”: 1 serving a week in pregnancy	“Best Choice”: 2–3 servings a week

Is halibut a flounder?

Biologically, yes. Halibut and flounder are both flatfish (order Pleuronectiformes), and NOAA places Pacific halibut in the family Pleuronectidae, the right-eyed flounders, the same family as winter flounder. NOAA notes that by about six months a young halibut’s left eye has migrated to the right side and the fish swims flat.

“Flounder” at the fish counter is a looser word. Summer flounder (fluke), southern flounder and Florida’s Gulf flounder are left-eyed fish in a separate family, Paralichthyidae, while winter flounder and halibut are right-eyed. Nobody sells halibut as “flounder,” and a thin flounder fillet should never be priced as halibut. The flounder names are untangled in our fluke vs flounder guide.

Which is bigger, halibut or flounder?

Halibut, by a huge margin. NOAA calls Pacific halibut “the largest species of flatfish”: up to 8 feet long and 500 pounds, with the biggest fish, nicknamed “barn doors,” more than 5 feet wide.

Flounder stays small. New Jersey’s Division of Fish and Wildlife gives summer flounder a maximum of 37 inches and 26 pounds, but that is a record-class fish. South Carolina DNR growth data put a 14-inch southern flounder at about 1.1 pounds and an 18-inch fish at 2.1 pounds. That is why flounder fillets are thin, often under half an inch, while a halibut portion can be an inch or two thick.

Do halibut and flounder taste different?

Yes, though both are mild white fish. NOAA describes halibut as “very mild and sweet,” with cooked meat that is “flaky, tender, and firm” and snow white. The flakes are large and the bite is dense and meaty, closer to grouper than to any other flatfish.

Flounder is softer and lighter. NOAA calls summer flounder’s flavor “delicate” and its texture “flaky and fine”; Florida’s agriculture department describes flounder as “firm white meat, delicate flake, fine texture, mild flavor.” Winter flounder is simply “mild” and “lean, boneless, and flaky.”

At the table the difference is weight and moisture: halibut eats like a steak, flounder like a thin, buttery sheet that parts under a fork. For deeper flavor notes, see what halibut tastes like and what flounder tastes like.

How should you cook halibut vs flounder?

Cook halibut like a steak: grill, roast at high heat, sear and finish in the oven, or poach. Halibut is lean, so pull it the moment it turns opaque.

Cook flounder fast and gently. FDACS notes that fillets under half an inch do not even need turning. Dredge in seasoned flour and pan-fry, sauté in butter with lemon, broil for a few minutes, or bake a whole flounder stuffed with crab or shrimp, the Southern classic. Flounder is also the thin-fillet fish of choice for a fish fry.

Which is healthier, halibut or flounder?

Both are lean, high-protein fish, and the differences are small. USDA FoodData Central lists raw halibut at 91 calories, 18.6 g protein and 1.33 g fat per 100 g, and raw flounder at 70 calories, 12.4 g protein and 1.93 g fat. Flounder has slightly more omega-3 (0.25 g EPA+DHA versus 0.19 g). Halibut has more vitamin D (4.7 µg vs 2.8 µg), selenium (45.6 vs 26.6 µg) and niacin, while flounder carries far more sodium (296 mg vs 68 mg).

Mercury is the one place they split. FDA puts flounder on its “Best Choices” list (two to three 4-ounce servings a week for pregnant and breastfeeding women and young children) and halibut on the “Good Choices” list (one serving a week), because big, long-lived predators accumulate more mercury. For everyone else, both are healthy choices.

Why does halibut cost so much more than flounder?

Supply and distance. NOAA reports U.S. halibut landings of about 20 million pounds in 2024, worth $78 million at the dock, roughly $3.90 a pound before processing and shipping, and 95 percent of it came from Alaska. The International Pacific Halibut Commission sets strict catch limits and a commercial season that usually runs March to November, and the fishery uses hook-and-line gear only.

Flounder is caught close to East Coast and Gulf ports, mostly by trawl, in larger volume: the 2026 commercial quota for summer flounder alone is 12.78 million pounds, and winter flounder sold for about $1.95 a pound at the dock in 2024. Menu prices move with the season (check current), but expect halibut at two to three times the price of flounder.

Flounder in Florida: gigging

Florida has three flounders: Gulf flounder along all Florida coasts, southern flounder north of the Loxahatchee and Caloosahatchee rivers on both coasts, and summer flounder mainly in the northeast, according to FDACS. Many are gigged rather than hooked. South Carolina DNR describes the method: fishermen patrol the shallows at night in shallow-draft boats with bow lights, pole across the flats, and spear the flounder the light reveals; in North Carolina in 2002, gig landings ran about 1.5 times the hook-and-line catch. Florida’s FWC regulates flounder with size and bag limits and seasonal rules, so check the current regulations before a trip.

Which should you order?

Grilled or blackened entrée: halibut. A thick portion stays juicy and holds together; flounder falls apart on a grate.
Fried fish basket or fish fry: flounder. Thin fillets crisp fast and the delicate flake is the point.
Stuffed whole fish: flounder, with crab stuffing.
Fish sandwich or tacos: flounder; halibut is wasted under slaw and sauce.

If neither is on the menu, Fish On Fire’s Gulf grouper and mahi fill the same roles: grouper for the meaty, large-flake bite, mahi for a dense, mild fillet. The mild fish chooser compares the rest of the white fish you are likely to see.

Bottom line

Halibut and flounder are relatives, not substitutes: halibut is the big, firm, pricey steak fish for the grill; flounder is the small, delicate, affordable fillet for the pan. For the closer matchup among firm white fish, read halibut vs cod.

Halibut vs Flounder: What's the Difference?