Flounder Nutrition Calculator — Calories & Nutrition per Serving

A 500g whole flounder produces approximately 175-200g of edible fillet — a 35-40% yield rate ^[1]. This is notably lower than round fish like salmon (~55% yield) or cod (~45% yield). The flat body structure means more surface area is bone and fin relative to edible flesh.

When purchasing whole flounder, this yield matters for accurate tracking: a 500g whole fish at the market produces only about 200g of cooked meat — roughly 172 kcal and 30.5g protein when baked. Buying fillets eliminates waste but costs more per gram ^[1].

Research on flatfish anatomy has confirmed that the unique bilateral body plan of Paralichthys species results in four thin fillets per fish (two from each side), each thinner at the edges — which is why flounder fillets cook significantly faster than equal-weight cod or haddock fillets ^[2].

Summer flounder (Paralichthys dentatus, also called 'fluke') and winter flounder (Pseudopleuronectes americanus) are different species named for their peak seasons — summer flounder moves inshore May through September, while winter flounder is caught closer to shore in colder months ^[1].

Nutritionally, both species fall under the USDA flatfish entry: 86 kcal, 15.2g protein, 2.37g fat per 100g cooked ^[1]. Summer flounder fillets are generally larger (0.5-2 kg whole) and thicker than winter flounder (0.3-1 kg), which affects cooking time but not nutritional value per gram.

Research comparing protein content and feed efficiency in flatfish species has found that environmental conditions such as water temperature and feed availability influence growth rate but produce minimal variation in the final amino acid and lipid composition of harvested fillets ^[3].

Flounder's macros (15.2g protein at 86 kcal) are modest compared to leaner, higher-protein fish like cod or haddock. But its micronutrient profile is where the value lies: 32.6mcg selenium (59% DV) and 3.5mcg vitamin D (18% DV) per 100g cooked ^[1].

A standard 127g fillet delivers 41.4mcg selenium (75% DV) and 4.4mcg vitamin D (22% DV) — plus 1.66mcg B12 (69% DV) and 392mg phosphorus (31% DV). Four micronutrients at meaningful daily value percentages from a single 109-calorie serving ^[1].

The phosphorus content (309mg per 100g) is particularly notable — more than double that of cod (138mg) and higher than haddock (278mg) or tilapia (204mg) — making flounder one of the most phosphorus-dense fish options per calorie ^[1].

Even a light pan-fry with minimal flour coating pushes flounder from 86 kcal to 160 kcal per 100g — an 86% increase ^[1]. The combination of absorbed cooking oil (~5.8g added fat) and flour coating (~5.8g carbs) accounts for nearly all of the added calories.

For a typical pan-fried flounder dinner (170g serving): 272 kcal, 24.7g protein, and 13.9g fat — compared to 146 kcal, 25.9g protein, and 4.0g fat for the same serving baked. The protein stays similar, but calories nearly double and fat triples ^[1].

A common tracking mistake: logging pan-fried flounder using the 'baked' entry underreports calories by approximately 74 kcal per 100g — over a 125-calorie error on a standard serving. Always select the correct cooking method when logging ^[1].

Stuffed flounder roulade — fillets rolled around a spinach and cheese filling — transforms the nutritional profile in unexpected ways. The composite dish has 138 kcal per 100g (60% more than plain baked), but the stuffing adds 85mg calcium (from cheese, vs. 25mg in plain fish), 30mcg folate (from spinach, vs. 6mcg), and 80mcg vitamin A (vs. 12mcg) ^[1].

A typical restaurant roulade weighs approximately 200-250g, delivering 276-345 kcal with 29.6-37g protein. The filling adds micronutrient diversity that plain fish lacks — particularly calcium, which most fish provide in minimal amounts ^[1].

For tracking, the key addition from the stuffing is 4.5g carbohydrates per 100g (from breadcrumbs in the filling) and an increase in sodium from 363mg to approximately 410mg. The spinach contributes negligible calories but meaningful vitamin A and folate ^[1].