How much protein is in canned tuna?

One of the cheapest complete proteins you can buy

Canned tuna is, gram for gram, one of the best protein values in any grocery store. The fish is a complete protein — it carries all nine essential amino acids your body can’t make on its own — and it’s exceptionally lean: light tuna canned in water runs under 1g of fat per 100g while delivering 25.5g of protein. That ratio is hard to beat. A serving costs a fraction of what the equivalent protein from chicken breast or Greek yogurt would, with no cooking and a multi-year shelf life. If you’re trying to eat more protein on a budget, this is close to the floor on price-per-gram.

It’s worth being precise about what “a serving” means here, because the can does most of the work. A standard 5 oz can is mostly fish once you pour off the water: drained, it lands around 4 oz of tuna and roughly 30g of protein — more for solid- or albacore-pack tuna. The 3 oz portion most labels quote comes out to about 22g. Either way you’re getting a dense, near-pure dose of protein with almost nothing else along for the ride.

The label gotcha: salt and packing medium

The USDA numbers above describe a specific product — light tuna, canned in water, without added salt, drained. That last part matters, because it’s not what’s usually on the shelf. Most supermarket canned tuna adds salt during processing, so the sodium on a real-world label is far higher than the ~50mg per 100g in the reference: often 180–300mg per serving. The protein and calories barely move; it’s the sodium line that changes. If you eat tuna daily, that’s the number to watch, and no-salt-added cans exist for exactly this reason.

The packing medium is the other variable. Tuna in water is the lean default — what you want if you’re counting calories, since the protein is high and the fat is negligible. Tuna in oil carries a similar amount of protein but soaks up fat and calories from the oil, and even a good draining leaves some behind. Neither is “wrong,” but they’re different tools: water for lean protein, oil for richness.

Light vs. albacore: the real buying decision

The choice that actually matters at the shelf isn’t the brand — it’s light tuna versus albacore (“white”). They’re different fish with a genuine tradeoff. Light tuna is mostly skipjack, a smaller species that’s lower in mercury; the FDA puts it in the “best choices” tier you can eat two to three times a week. Albacore is a larger fish that concentrates roughly three times more mercury, which is why guidance caps it at about one serving a week. The flip side: albacore brings more omega-3 fats and a firmer, milder fillet. So the rule of thumb is simple — light for frequent eating and lower mercury, albacore for the omega-3 boost in smaller doses. For most people rotating tuna into a weekly routine, light is the safer everyday pick.

Hitting a protein target with tuna

Because the macros are so clean, tuna is easy to build a day around. At roughly 22g per 3 oz and 30g+ per drained 5 oz can, a single can covers a meaningful slice of most daily protein goals — useful whether you’re aiming for the general 0.8g per kg of body weight or the higher intakes active people target. If you’re not sure what your own number should be, our guide on how much protein per day walks through it. And if you’d rather skip the math on sodium, mercury, and packing oil entirely, the graded cans below are scored on exactly those tradeoffs so you can pick one that fits.