Crab Weight Guide- Average Weights by Species
Crab Weight by Species: What You're Actually Getting
Most people grab crabs without checking the weight. That's a mistake. The weight tells you exactly what you'll pay for—meat, shell, and everything in between. Different species vary wildly. A 2-pound king crab looks tiny next to a 10-pound coconut crab. Here's the breakdown you actually need.
Average Crab Weights by Species
Weights below are for adult crabs. Juveniles are always lighter. If you're buying live crabs, expect slight variations from these averages.
| Species | Average Weight | Meat Yield |
|---|---|---|
| Blue Crab | 0.5 – 1.5 lbs | 15 – 20% |
| Dungeness Crab | 1.5 – 3 lbs | 25 – 30% |
| King Crab (Alaskan) | 6 – 20 lbs | 25 – 30% |
| Snow Crab | 2 – 5 lbs | 20 – 25% |
| Stone Crab | 0.5 – 1 lb (claws only) | 30 – 40% |
| Hermit Crab | 0.1 – 0.5 lbs | N/A (not eaten) |
| Horseshoe Crab | 2 – 10 lbs | Not typically harvested |
| Coconut Crab | 5 – 10 lbs | Rarely eaten |
Stone crabs are an outlier. You buy the claws only. The rest of the crab goes back into the water. That's why the weight seems low—because you're not getting the whole animal.
Why Weight Actually Matters
Weight determines two things: what you pay and what you eat. If you see "live blue crabs" at $8 per pound, a 1-pound crab costs $8. But only about 20% of that crab is edible meat. So you're paying $8 for roughly 3.2 ounces of crab. Do the math before you buy.
Shell weight accounts for the rest. Crabs have thick exoskeletons that add nothing to your plate. The larger the crab, the thicker the shell—and sometimes the worse the meat-to-shell ratio.
How to Weigh a Crab
Weighing Live Crabs
Use a kitchen scale. Place the crab in a container first, then tare the weight. Don't weigh the crab loose—it'll claw you and escape.
For live crabs sold at fish markets, most vendors list the weight before cooking. Ask to see it on the scale. If they refuse, walk away.
Weighing Cooked Crabs
Cooked weight is typically 10-15% higher than live weight due to water absorption. If you buy steamed crabs, the weight includes any added liquid or ice.
For accurate meat estimates, use the live weight. It's the only honest number.
Estimating Without a Scale
You can eyeball it:
- Your fist = roughly 1 pound for a blue crab
- Two fists = roughly 2-3 pounds for a Dungeness crab
- Both hands together = 6+ pounds for a king crab
This isn't precise. But it keeps you from getting completely ripped off at the fish market.
Factors That Affect Crab Weight
Weight isn't static. Several things change what you'll see on the scale:
Molting
Crabs shed their shells to grow. A newly molted crab has a soft shell and weighs less than a hard-shelled crab of the same age. Soft-shell crabs are lighter but easier to eat whole. Hard-shell crabs are heavier but require more work to crack.
Water Content
Live crabs hold water in their bodies. This can account for 5-10% of total weight. After cooking, some of that water evaporates or drips away.
Egg Mass
Female crabs carrying eggs weigh more. If you buy egg-bearing females, you're paying for eggs you might not want. Some markets discount these. Know what you're getting.
Season
Crabs are heaviest in late fall and winter—right before breeding season. They're lightest in late spring and summer after spawning. If you buy in May, expect smaller weights than December.
Getting Started: What to Buy
Here's the practical part:
- For crab boils: Blue crabs, 1-2 lbs each. Buy 2-3 per person if they're the main dish.
- For elegant meals: Dungeness crabs, 2-3 lbs each. One per person is enough.
- For special occasions: King crab legs. A 10-pound cluster feeds 4-6 people.
- For sustainability: Snow crabs are cheaper and sustainable, but smaller. Expect 2-3 legs per person.
Don't buy the cheapest option. Check the weight, calculate the meat, then decide. A $5 cheaper crab that weighs 30% more shell is a bad deal.
The Bottom Line
Crab weight tells you everything you need to know about value. Use the table above as your reference. Calculate meat yield before you checkout. And always weigh live crabs when possible—it's the only way to know what you're actually paying for.