Calories in Tuna
How many calories are in tuna? A can of tuna in water has about 100 calories and a 3-oz serving about 73. See a full tuna calorie and macros table.
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Quick answer
A 5-ounce can of tuna packed in water (drained) has about 100 calories, while a 3-ounce serving has about 73 calories. Tuna packed in oil has roughly double the calories of tuna in water.
How Many Calories Are in Tuna?
Tuna is one of the leanest, most protein-dense foods around, which makes it a dieter’s favorite. A standard 5-ounce can of tuna in water (drained) has about 100 calories, and a 3-ounce serving has about 73 calories. The biggest variable is the packing liquid: tuna in oil has roughly double the calories of tuna in water because the fish soaks up some of the oil.
Tuna’s calories come almost entirely from protein, with very little fat (when packed in water) and zero carbohydrate. That combination gives it an exceptional protein-to-calorie ratio.
Tuna Calories by Serving Size
| Serving | Amount | Calories | Protein (g) | Fat (g) | Carbs (g) |
|---|---|---|---|---|---|
| Tuna in water (3 oz) | 85g | ~73 | 16 | 1 | 0 |
| Tuna in water (5 oz can) | 142g | ~100 | 23 | 1.5 | 0 |
| Tuna in oil (3 oz) | 85g | ~150 | 16 | 7 | 0 |
| Fresh tuna steak (3 oz) | 85g | ~110 | 25 | 1 | 0 |
| 100 grams (in water) | 100g | ~86 | 19 | 1 | 0 |
These figures are for plain drained tuna. Tuna salad made with mayonnaise jumps to roughly 190 to 300 calories per half cup, depending on how much mayo is used, so the mix-ins drive the calories.
Macros and Nutrition in Tuna
Tuna delivers an outstanding amount of complete protein for very few calories. Beyond protein, it provides vitamin B12, selenium, niacin, vitamin D and phosphorus. Fresh and certain canned tuna also contain omega-3 fatty acids, though usually less than fatty fish like salmon.
With about 22 to 24 grams of protein in a single water-packed can for only around 100 calories, tuna is one of the most efficient protein sources available. This is why it is a staple for people building muscle or cutting calories while preserving lean mass.
Tuna in Water vs Oil vs Tuna Salad
The packing medium and preparation matter far more than the fish itself. Tuna in water is the leanest option. Tuna in oil adds fat and calories but also flavor and a richer texture. Tuna salad’s calories depend almost entirely on the mayonnaise — using light mayo, Greek yogurt or mustard can keep a serving near 120 calories, while a heavy hand with full-fat mayo can push it past 300.
Is Tuna Good for Weight Loss?
Tuna is close to an ideal weight-loss food, especially the water-packed variety. It is extremely high in protein, low in calories, portable and shelf-stable. The main caution is mercury: light tuna is fine in moderation, while albacore (white) tuna should be limited. For the lowest calories, choose tuna in water and dress it with lemon, mustard, herbs or a small amount of Greek yogurt rather than full-fat mayonnaise.
Frequently Asked Questions
How many calories are in a can of tuna?
A standard 5-ounce can of tuna packed in water, drained, contains about 100 to 110 calories and roughly 22 to 24 grams of protein. A can packed in oil has about 200 calories due to the absorbed oil.
How many calories are in tuna in water vs oil?
Tuna in water is much leaner, at about 73 calories per 3-ounce serving. Tuna in oil has about 150 calories per 3 ounces because the fish absorbs some of the packing oil, adding fat and calories.
Is tuna good for weight loss?
Yes, tuna is one of the best foods for weight loss. It is very high in protein and low in calories and fat, especially when packed in water, making it extremely filling for very few calories.
How much protein is in a can of tuna?
A 5-ounce can of tuna in water provides about 22 to 24 grams of protein. This high protein-to-calorie ratio is why tuna is a staple for dieters, athletes and bodybuilders.
Is canned tuna safe to eat often?
Canned light tuna can generally be eaten a few times a week, but albacore (white) tuna is higher in mercury, so health authorities suggest limiting it. Pregnant people should follow specific seafood guidance.
Sources
- FoodData Central — food composition database — U.S. Department of Agriculture (USDA)