A typical 3 oz cooked serving of mackerel contains 20.2 grams of protein (23.8 g per 100 g), which makes it a very good source of protein. That covers roughly 40% of the 50 g reference Daily Value, so it can anchor a high-protein meal for the day.
Protein accounts for roughly 36% of the calories in mackerel, making it very protein-dense. The rest comes from fat and carbohydrate, so it adds a solid amount of protein while still carrying real energy - useful when you are eating to a calorie target rather than under one.
Among the 121 seafood in the database, mackerel ranks 47th by protein per serving, and 148th out of all 796 foods on the site. Set against ahi tuna (raw), another seafood entry in the database, a serving carries about 0.5 g less protein (ahi tuna (raw) has 20.7 g per 3 oz raw).
It is a complete protein - it supplies all nine essential amino acids in adequate amounts, so it can carry a meal's protein on its own. The serving above is measured by weight at 85 g. The per-100 g figure lets you compare it directly against any other food here, whatever its serving.
Source: USDA FoodData Central #175120 - "Fish, mackerel, Atlantic, cooked, dry heat" (SR Legacy, published 4/1/2019). Values are the published reference figures for that record, not lab measurements for a specific brand or batch.
Quick answers
Mackerel protein FAQ
How much protein is in mackerel per 100 g?
Mackerel has 23.8 g of protein per 100 g. A typical 3 oz cooked serving (85 g) provides 20.2 g.
Is mackerel a complete protein?
Yes. Mackerel is a complete protein - it supplies all nine essential amino acids in adequate amounts, so it can carry a meal's protein on its own.
How much of the Daily Value does a serving of mackerel cover?
A 3 oz cooked serving of mackerel contains 20.2 g of protein, about 40% of the 50 g reference Daily Value.
Is mackerel a good source of protein?
Mackerel is a very good source of protein, and about 36% of its calories come from protein, which makes it very protein-dense. Set against ahi tuna (raw), another seafood entry in the database, a serving carries about 0.5 g less protein (ahi tuna (raw) has 20.7 g per 3 oz raw).