Crabs are one of the most protein-packed lean seafood choices, but the calories on your plate can vary widely depending on the species, the cut, and how much butter gets involved. A 100-gram portion of plain steamed crab meat typically contains only 86–97 calories, while a king crab leg dipped in melted butter can quickly turn into a much bigger energy investment.
This crab calorie calculator helps you estimate the calories in your serving, plus the protein, for five popular crab varieties: blue, Dungeness, king, snow, and stone crab. Enter your portion in grams, ounces, or cups, choose your butter addition, and get an instant, realistic breakdown. The tool also shows separate calorie counts for crab meat and butter, plus a protein estimate.
It's perfect for seafood lovers tracking calories, athletes hitting protein targets, or anyone planning a crab feast without the guesswork.
Crab Calorie Calculator
Estimate calories and protein for popular crab varieties, including optional melted butter.
Step-by-Step Guide
- Select your crab variety. Calorie density differs by species: Dungeness is the leanest at about 86 kcal per 100 g of cooked meat, while king crab is the richest at about 97 kcal per 100 g. If your crab is not listed, blue crab is a good middle-ground default.
- Enter your portion. You can type grams, ounces, or cups of flaked meat. The calculator converts everything to grams internally: 1 oz = 28.35 g, and 1 cup of flaked crab meat weighs roughly 135 g. If you weigh a whole crab, remember that only the edible meat counts — shell, cartilage, and gills should be excluded or estimated separately.
- Choose your butter option. Each tablespoon of melted butter adds about 102 kcal. Leaving butter off keeps the meal very lean; adding 2 tbsp can nearly double the calories of a modest serving, so this choice often matters more than the crab variety.
- Calculate and read the breakdown. The result panel shows total calories, calories from crab meat alone, calories added by butter, and the protein in the crab meat. Use the step-by-step breakdown to log each part in your food tracker.
The Math Behind It
The calculator uses average values for cooked, edible crab meat drawn from the USDA FoodData Central database. For each variety, the calorie and protein values per 100 g are applied proportionally to your portion size:
Calories from crab = (grams ÷ 100) × kcal per 100 g
Protein = (grams ÷ 100) × protein per 100 g
Total calories = calories from crab + butter calories
When you enter ounces, the tool multiplies by 28.35 to convert to grams; when you enter cups, it multiplies by 135 g, the approximate weight of a cup of flaked crab meat. The butter math is straightforward: 1 tbsp of salted butter contributes about 102 kcal and the tool multiplies by the number of tablespoons you selected. Because crab meat is naturally low in fat, rounding to the nearest whole calorie is fine for daily tracking — differences between reputable sources are typically only 5–10 kcal per 100 g.
Crab Nutrition Reference Table
Values below are for cooked, edible meat with no added fat. Figures vary slightly by season, water content, and cooking method.
| Crab variety | Calories (kcal / 100 g) | Protein (g / 100 g) | Approx. meat yield |
|---|---|---|---|
| Blue crab | 87 | 18.1 | 3–4 oz from a 1 lb crab |
| Dungeness crab | 86 | 17.4 | ~1 lb from a 2–3 lb crab |
| King crab | 97 | 19.4 | 4–6 oz per leg |
| Snow crab | 90 | 18.3 | ~2 oz per leg |
| Stone crab | 95 | 19.0 | 2–3 oz per claw |
Use the meat yield column to estimate how many crabs you need for a meal. Whole-crab weight is a poor guide because shell and cartilage typically make up 50–75% of the total weight.
Worked Examples
Example 1 — Blue crab snack. 120 g of steamed blue crab with no butter: 120 ÷ 100 × 87 = 104 kcal, plus 120 ÷ 100 × 18.1 = 21.7 g protein. A generous, filling snack for barely over 100 kcal.
Example 2 — King crab leg with butter. One king crab leg yields about 5 oz (142 g) of meat. With 1 tbsp of butter: 142 ÷ 100 × 97 ≈ 138 kcal from crab + 102 kcal from butter = 240 kcal total, with roughly 28 g protein. Skip the butter and the same leg stays under 140 kcal.
Example 3 — Snow crab cluster (1 cup). A typical cluster yields about 1 cup (135 g) of meat. With 2 tbsp of butter: 135 ÷ 100 × 90 = 122 kcal from crab and 204 kcal from butter = 326 kcal total, with 24.7 g protein. Notice how the butter becomes the dominant calorie source.
Common Mistakes to Avoid
Weighing shell-on crab. Shell, cartilage, and gills can make up the majority of a whole crab's weight. Always weigh only edible meat, or assume a 25–35% meat yield from a shell-on crab. Treating a whole 2 lb crab as 2 lb of meat would overestimate calories by 3–4 times.
Forgetting the cooking fat. Steamed crab is nearly fat-free, but butter, garlic butter, mayonnaise dips, or breading add significant calories. Each tablespoon of butter adds about 102 kcal — log it as a separate line item if you track your intake.
Confusing raw and cooked weight. Crab meat loses moisture as it cooks, so cooked meat has a slightly higher calorie density per 100 g. This tool uses cooked values, which match what you actually eat; if a recipe lists raw weights, expect the cooked yield to be roughly 80–85% of raw.
Frequently Asked Questions
Is crab good for weight loss?
Yes — plain crab meat is one of the leanest animal proteins available, with 86–97 kcal and 17–19 g of protein per 100 g. Protein promotes satiety, and the low calorie density lets you enjoy a generous portion. Butter, sauces, and sides are where the calories add up.
Why do calorie values differ between sources?
Values vary by species, season, water content, cooking method, and whether the data is for raw or cooked meat. Databases also round values differently. The practical differences are small — about 5–10 kcal per 100 g — so any reputable source gives a usable estimate for daily tracking.
How much meat do I get from a whole crab?
A 1 lb blue crab yields roughly 3–4 oz of meat, a 2–3 lb Dungeness yields about 1 lb, and a single king crab leg provides 4–6 oz. Yield depends on season and molt stage; soft-shell crabs are eaten whole, so nearly all of their weight is edible.
Does the calculator include sodium or cholesterol?
No — it focuses on calories and protein, which covers most daily tracking. Crab is naturally higher in cholesterol, but dietary cholesterol has a modest effect on blood cholesterol for most people. For sodium, a 100 g serving of crab contains roughly 250–300 mg before any added salt.
How should I store leftover crab?
Refrigerate cooked crab within two hours and use it within 3–4 days. Wrap it tightly to keep it moist and reheat gently, since repeated heating dries out the meat. For safe handling details, see the FDA guidance on selecting and serving fresh and frozen seafood.