66 %
Selenium contributes to the normal function of the immune system, to normal thyroid function and to the maintenance of normal hair and nails.
How many calories are in flounder?
115kcal
in a 140 g fillet
82 kcal per 100 g.
Source: UK CoFID 2021, record 16-040. Checked 5 October 2026.
2.5 gFat
23 gProtein
0 gFibre
66 %Daily selenium
What’s in a 140 g fillet
More than half of a fillet is water, which is why the calories stay low. What is left is mostly protein.
- 2.5 gFat
- 23 gProtein
- 114 gWater
- 0.8 gMinerals and the rest
Below average for fish and seafood
Flounder is 82 kcal per 100 g. The 170 fish and seafood in this database average 138.
Flounder82
Fish and seafood average138
Low in sugar and salt
Low sugars and low salt by UK labelling rules, per 100 g.
Sugars, per fillet0 g
Salt, per fillet0.32 g
Vitamins and minerals in flounder
Three of the 18 reach the “high in” level, led by selenium.
A source of
Only a trace
- Vitamin D
- Vitamin C
Show all 18 with amounts
Selenium0.0364 mg, 66 %
Niacin (vitamin B3)9.1 mg, 57 %
Vitamin B120.0014 mg, 56 %
Phosphorus266 mg, 38 %
Vitamin B60.35 mg, 25 %
Iodine0.035 mg, 23 %
Chloride182 mg, 23 %
Riboflavin (vitamin B2)0.29 mg, 21 %
Potassium420 mg, 21 %
Thiamin (vitamin B1)0.2 mg, 18 %
Magnesium32.2 mg, 8.6 %
Folate0.0154 mg, 7.7 %
Zinc0.7 mg, 7 %
Calcium37.8 mg, 4.7 %
Vitamin E0.5 mg, 4.2 %
Copper0.04 mg, 4.2 %
Iron0.56 mg, 4 %
Manganese0.06 mg, 2.8 %
Badges use the UK legal thresholds per 100 g: 15 % of the reference intake for “source of”, 30 % for “high in”. A trace is shown as “trace” and never counts.
What flounder doesn’t give you. And where to find it.
No recorded vitamin D or vitamin C, and only 2.9 % of the iron reference intake per 100 g.
Vitamin D
Tracein flounder
Find it inBloater, grilled500 % per 100 g
Vitamin C
Tracein flounder
Find it inCherries, West Indian2150 % per 100 g
Iron
2.9%in flounder, per 100 g
Find it inThyme, dried, ground883 % per 100 g
100 mgVitamin C, 125 %
0.075 mgSelenium, 136 %
0.00125 mgVitamin D, 25 %
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Made in Cambridgeshire
Made in the UK since 1998, with every nutrient and its declared amount listed on the label.
Flounder against other fish and seafood
Per 100 g, sardines (raw) has the most selenium in this comparison, followed by haddock (smoked, raw).
0.051mg
0.038mg
0.03mg
0.028mg
0.026mg
0.021mg
Sardines, raw+0.025 mg
Haddock, smoked, raw+0.012 mg
Cod, steamed+0.004 mg
Flounder, rawthis page
Whiting, raw−0.005 mg
All values per 100 g, from the same dataset. Differences are against flounder.
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Questions about flounder
What the numbers say to the questions people actually search.
How many calories are in a portion of flounder?
A typical portion (140 g, one fillet) gives 115 kcal. Per 100 g the figure is 82 kcal.
Is flounder high in selenium?
Yes. Flounder, raw has 0.026 mg selenium per 100 g, 47 % of the NRV, above the 30 % threshold for a “high in” claim.
Which vitamins and minerals does flounder have most of?
By share of the daily reference intake: selenium (0.026 mg, 47 %), niacin (6.5 mg, 41 %) and vitamin B12 (0.001 mg, 40 %) per 100 g.
Is flounder a good source of protein?
Flounder, raw has 16.4 g protein per 100 g, 80 % of the energy, which meets the UK threshold for “high protein”.
How these numbers were made
Every figure comes from the UK Composition of Foods Integrated Dataset (CoFID), 2021 edition, record 16-040, Flounder, raw, published by Public Health England under the Open Government Licence v3.0. Main data references: Fish and Fish Products Supplement, 1993. Values are per 100 g of the edible part; a fillet is 140 g, one fillet, the usual UK portion for fish and seafood. Reference intakes follow Regulation (EU) 1169/2011 Annex XIII as retained in GB law; “source of”, “high in” and “low” follow Regulation (EC) 1924/2006, assessed per 100 g. Function lines are the authorised wording from the GB register of nutrition and health claims, credited to the nutrient. Energy is rounded to the whole kcal and kJ; other amounts to one decimal, or two below 1. A trace is shown as “trace” and never gets a figure or a badge; a nutrient never analysed is left off the page. We start from the dataset’s 2,887 records and keep 2,322: records weighed with bone, shell or skin, alcoholic drinks, infant foods, brand-named products, records with fewer than eight measured vitamins and minerals and near-identical variants are left out. Group context uses the 170 fish and seafood kept from the dataset; a rank counts only the foods with a measured figure for that nutrient. Food images are illustrations from Ingredient Atlas, released under CC0; they show the food, not the measured sample, and where no illustration of the exact food exists the nearest one is shown (here: Frozen Fish Fillets). Checked 5 October 2026. Contains public sector information licensed under the Open Government Licence v3.0.
More fish and seafood
From the same group, with calories per 100 g, and the foods with the most selenium.
More fish and seafood
- Cod, in batter, fried, takeaway240 kcal
- Haddock, fillets, in flour, fried in dripping138 kcal
- Katla, raw100 kcal
- Oysters, raw65 kcal
- Rock Salmon/Dogfish, in batter, fried295 kcal
- Shrimps, dried245 kcal
- All 170 fish and seafood
Most selenium
- Crab, brown meat, purchased cooked0.225 mg
- Shrimps, dried0.17 mg
- Prawns, standard, dried0.163 mg
- Kidney, pig, fried0.27 mg
- Brazil nuts, kernel only0.254 mg
- Kidney, pig, stewed0.25 mg
- Selenium guide