How many calories are in tuna?

For a standard 3-ounce serving, tuna packed in water and drained is often around 100 to 120 calories. Tuna packed in oil and drained is usually higher, often closer to 170 to 200 calories for the same portion. Fresh tuna steaks also vary, but many raw tuna cuts land in a similar lean-protein range per 3 ounces.

The big reason for the difference is fat. Tuna itself is naturally lean, but oil-packed tuna absorbs extra calories from the oil. If you are tracking calories closely, the label matters more than the word “tuna” alone.

Calories in common tuna serving sizes

A tuna pouch or can is often more than one serving, so check the label instead of guessing. If a can lists two servings, eating the whole can means doubling the calories and protein on the label.

As a rough guide: 1 ounce of water-packed tuna is about 35 to 40 calories, 3 ounces is about 100 to 120 calories, and 5 ounces is often around 170 to 200 calories. Oil-packed tuna can run several dozen calories higher per serving, even after draining.

Tuna salad is a different story. Mayo, cheese, crackers, and bread can add far more calories than the tuna itself. A tuna sandwich can easily go from a 100-calorie protein base to a 400- to 600-calorie meal depending on the extras.

What tuna gives you besides calories

Tuna is valued because it delivers a lot of protein for relatively few calories, especially in water-packed form. That makes it useful for people trying to stay full while keeping meals lighter. It also provides important nutrients such as selenium and, depending on the type, some omega-3 fats.

If you are comparing protein foods, tuna is often more calorie-efficient than many deli meats, creamy salads, or fried fish. Still, the healthiest choice depends on the whole meal, not just the fish itself.

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How to keep tuna lower in calories

Choose tuna packed in water instead of oil when your goal is fewer calories. Drain it well, then build flavor with mustard, Greek yogurt, salsa, herbs, lemon juice, or chopped celery instead of heavy mayo.

Pay attention to what you serve with it. Tuna over salad greens, in lettuce wraps, or with whole-grain toast is usually lighter than tuna mixed into a pasta salad or piled with creamy dressing.

If you eat tuna often, also think about variety. Mixing tuna with other protein sources like salmon, beans, eggs, chicken, or tofu keeps your diet more balanced and prevents meal burnout.

Tips

• Check whether your tuna is packed in water or oil before logging calories.
• Use the serving size on the label; many cans contain more than one serving.
• Drain tuna thoroughly to reduce extra calories from liquid or oil.
• Keep add-ins simple if you want a lower-calorie meal: mustard, yogurt, lemon, and herbs work well.
• Watch the calories in tuna salad extras like mayo, cheese, and crackers.