A 100-gram serving of raw squid contains about 15.6 grams of protein, with only 92 calories. That makes squid one of the more protein-dense seafood options available, delivering a high ratio of protein to calories with very little fat.
Protein by Serving Size
How much protein you get depends on how much squid you eat. A standard 3-ounce (roughly 85-gram) portion of uncooked squid provides about 13.2 grams of protein. Scale that up to 100 grams and you’re at 15.6 grams. A larger 6-ounce portion, which is closer to what you might get at a restaurant, lands around 26 grams of protein.
For context, squid sits in a similar range to shrimp and is slightly below chicken breast, which packs about 31 grams per 100 grams. But squid has an advantage over many other protein sources: it’s extremely low in fat. A 3-ounce serving contains just 0.3 grams of saturated fat, making it leaner than most cuts of meat, poultry, and even many other types of fish.
Squid Is a Complete, High-Quality Protein
Not all protein sources are created equal. What matters beyond the gram count is whether a food provides all nine essential amino acids your body can’t make on its own. Squid does. Researchers analyzing three different squid species found 18 amino acids present in the meat, with particularly high levels of lysine, leucine, and arginine.
The ratio of essential to total amino acids in squid ranges from about 43% to 45%, which exceeds the benchmark set by the FAO and WHO for high-quality protein. In fact, squid protein is comparable to egg protein, which is often used as the gold standard for amino acid completeness. The only amino acid that comes in slightly below the reference pattern is valine, and even that scores at 97.2% of the ideal level. For practical purposes, squid protein is nutritionally complete.
What Else You Get With That Protein
Squid is unusually rich in certain micronutrients. A 100-gram serving of raw squid delivers about 200% of the recommended daily intake of vitamin B12 for adults, a nutrient your body cannot produce and must get from animal foods. B12 is essential for nerve function and red blood cell production, so a single serving of squid covers you for the entire day and then some.
The same serving also provides 88% to 110% of the daily selenium recommendation (the range depends on sex). Selenium supports your body’s antioxidant defenses, helping protect cells from damage. Squid is also a meaningful source of copper and vitamin B6. All of this comes packaged with those 15.6 grams of protein at just 92 calories, which is a remarkably nutrient-dense profile.
The Cholesterol Question
Squid does contain a notable amount of cholesterol: roughly 198 milligrams in a 3-ounce serving. That number sometimes raises eyebrows, but it needs context. Squid is very low in saturated fat, which is the dietary factor most strongly linked to raising blood cholesterol levels. The small amount of fat squid does contain includes monounsaturated and polyunsaturated fats, both considered heart-friendly.
Squid also contains omega-3 fatty acids, the same type of fat that makes salmon a recommended food for cardiovascular health. The key variable is preparation. Plain grilled, steamed, or sautéed squid keeps the fat content low. Frying squid into calamari adds significant amounts of oil and often batter, which raises total fat and saturated fat considerably, turning an otherwise lean protein into something much heavier.
How Cooking Changes the Numbers
Cooking squid reduces its water content, which concentrates the protein per gram of finished food. You can expect cooked squid to contain roughly 17 to 18 grams of protein per 100 grams, depending on the method. Grilling, baking, and sautéing all preserve the lean profile. Deep frying, on the other hand, can more than double the calorie count while adding several grams of fat per serving. If your goal is maximizing protein while keeping calories low, stick with dry-heat or light-oil methods.
Mercury Levels in Squid
Squid is one of the lowest-mercury seafood options you can eat. FDA testing found an average mercury concentration of just 0.02 parts per million across sampled squid, far below the 0.15 ppm threshold for the agency’s “Best Choices” category. That puts squid in the safest tier of seafood, cleared for 2 to 3 servings per week even for pregnant women and young children. If mercury is a concern that has kept you from eating more seafood, squid is one of the least problematic options available.
How Squid Compares to Other Seafood
- Shrimp: Similar protein (about 14 grams per 100g raw), also very low in fat and mercury. Nearly interchangeable with squid nutritionally.
- Salmon: Higher protein (about 20 grams per 100g) and much higher in omega-3s, but also higher in total calories and fat.
- Tuna: Higher protein (around 23 to 25 grams per 100g), but mercury levels vary widely by species, and some types fall into the “limit consumption” category.
- Cod: Comparable protein (about 18 grams per 100g) with a similarly lean profile, though lower in B12 and selenium than squid.
Squid holds its own against all of these, particularly when you factor in its exceptional B12 and selenium content, minimal mercury, and versatility in cooking.