Calories in Crab: Nutrition Facts & Serving Sizes
Per 3 oz (85g)
Per 100g
Source: USDA FoodData Central, SR Legacy, March 2026.
Three ounces of crab (85g) contains 74 calories with 15.4g of protein, 0g carbs, and 0.9g of fat. Per 100g, crab provides 87 calories with 18.1g of protein, 0g carbs, and just 1.1g of fat. Vitamin B12 is exceptional at 9mcg per 100g, covering about 375% of the daily value. Selenium is 37.4mcg per 100g (68% daily value). Zinc provides 3.5mg per 100g (about 32% daily value), making crab one of the best seafood sources of zinc. Folate provides 44mcg per 100g. Sodium is moderate at 293mg per 100g. Crab is a lean, high-protein shellfish with outstanding micronutrient density. It is one of the best protein sources available per calorie.
Nutrition Highlights
Calories by Serving Size
| Serving | Cal | Protein | Carbs | Fat | Fiber |
|---|---|---|---|---|---|
| 3 oz (85g) | 74 | 15.4g | 0g | 0.9g | 0g |
| 1 crab (21g) | 18.3 | 3.8g | 0g | 0.2g | 0g |
| 100g | 87 | 18.1g | 0g | 1.1g | 0g |
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Full Nutrition Facts (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 87 | 4% |
| Protein | 18.1g | 36% |
| Total Fat | 1.1g | 1% |
| Saturated Fat | 0.2g | 1% |
| Total Carbohydrates | 0g | |
| Dietary Fiber | 0g | |
| Sugars | 0g | |
| Sodium | 293mg | 13% |
| Cholesterol | 78mg | 26% |
Vitamins & Minerals (per 100g)
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Saturated Fat | 0.2g | 0% |
| Cholesterol | 78mg | 26% |
| Calcium | 89mg | 7% |
| Iron | 0.7mg | 4% |
| Potassium | 329mg | 7% |
| Vitamin A | 2mcg | 0% |
| Vitamin C | 3mg | 3% |
| Vitamin B6 | 0.2mg | 12% |
| Vitamin B12 | 9mcg | 375% |
| Magnesium | 34mg | 8% |
| Phosphorus | 229mg | 18% |
| Zinc | 3.5mg | 32% |
| Selenium | 37.4mcg | 68% |
| Folate | 44mcg | 11% |
| Thiamin (B1) | 0.1mg | 8% |
| Niacin (B3) | 2.7mg | 17% |
% Daily Values based on a 2,000 calorie diet (FDA reference).
Health Benefits of Crab
Crab is a nutritional powerhouse for anyone focused on lean muscle building. The protein content at 18.1g per 100g with only 1.1g of fat delivers an outstanding protein-to-calorie ratio. A 3 oz serving provides 15.4g of protein for just 74 calories.
The vitamin B12 content at 9mcg per 100g is extraordinary, covering about 375% of the daily value. B12 is essential for energy production, nerve function, and red blood cell synthesis. It is particularly important for those who train regularly and need efficient oxygen delivery to working muscles.
Zinc at 3.5mg per 100g is notably high for seafood, covering about 32% of the daily value. Zinc is critical for testosterone production, immune function, and protein synthesis. Regular crab consumption can meaningfully contribute to zinc intake.
Selenium at 37.4mcg per 100g covers 68% of the daily value, supporting antioxidant defense and thyroid hormone regulation. Folate at 44mcg per 100g (11% daily value) supports DNA synthesis and cell repair.
For meal prep, crab legs, crab cakes, or canned crab make excellent lean protein options. Real crab is more nutritious than imitation crab, which is made from processed fish and has different macros.
Dietary Considerations
Crab is keto-friendly with zero carbs and very low fat. It is excellent for weight loss at 87 cal/100g with high protein. It is naturally gluten-free. It is not vegan. The shellfish allergy is one of the most common food allergies, so crab should be avoided by anyone with a shellfish or crustacean allergy. Sodium at 293mg per 100g is moderate.
Daily Intake (100g)
100g of crab provides 4% of a 2,000-calorie diet.
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Frequently Asked Questions
How many calories in crab?
A 3 oz serving of crab (85g) contains about 74 calories. Per 100g, crab has 87 calories. A small crab (21g) contains about 18 calories.
Is crab good for weight loss?
Yes, crab is excellent for weight loss. At 87 calories per 100g with 18.1g of protein, it is one of the most protein-dense, low-calorie seafoods available. The high protein promotes satiety while keeping calories very low.
How much protein is in crab?
Crab has 18.1g of protein per 100g. A 3 oz serving (85g) provides 15.4g of protein. The protein quality is excellent with all essential amino acids present.
Is crab high in zinc?
Yes, crab is an excellent source of zinc at 3.5mg per 100g (about 32% daily value). A 3 oz serving provides about 3mg of zinc. This makes crab one of the better seafood sources of zinc, which supports testosterone production and immune function.
How does crab compare to shrimp nutritionally?
Both are lean, high-protein shellfish. Crab has 87 calories and 18.1g protein per 100g, while shrimp has about 99 calories and 24g protein per 100g. Crab is slightly lower in calories but shrimp has more protein per 100g. Both are excellent choices.
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