The full guide
Read straight through, or use the seafood notes above to keep buying, cooking and serving simple.
How to Cook a Live Crab
IMPORTANT...
Make sure that your crab is still alive before cooking it. When a crab dies bacteria will quickly destroy the meat so it is important to either cook the crab while it is still alive or immediately after it has died.
A crab that has limp claws or whose antennae isn't twitching when you pick it up is close to death and should be cooked immediately.
Getting your crab in advance
It is possible to get a crab in advance of a special occasion but we would advise cooking it when you get it and then keeping the cooked crab in the fridge until it is required.
A cooked crab can be kept in the fridge for a couple of days.
Cooking a crab humanely
Nobody likes the thought of killing something and many people, including chefs, do not like cooking live crabs. While commercial shellfish processors are now required to use a stun gun to kill shellfish, this is not the case for domestic consumers.
The current guidance by Seafish, working alongside the Shellfish Association of Great Britain (SAGB) and the Crab and Lobster Management Group (CMG) is as follows:
"In terms of despatch at home by consumers, current advice is that crab should not be boiled alive (either by placing in cold water which is raised to a boil or already boiling water). Instead they should be put in the freezer for 30-60 minutes, before being placed immediately into boiling water" - Seafish UK 03.08.22
We will monitor this and change the advice should anything change.
For more information about shellfish welfare please visit https://www.seafish.org/about-us/news-blogs/seafood-industry-focuses-on-crustacean-welfare/
Crab Cooking Times
Imperial
Metric
Cooking Time
1 - 1 ¼ lb.
500g
12 - 15 mins
1 ¼ - 2 lb.
500g-900g
15 - 20 mins
2-3 lb.
900-1350g
20 - 25 mins
3-7 lb.
1350-3kg
25 - 30 mins
Over 7lb
Over 3kg
3 mins per lb / 500g
When your crab is cooked, remove it from the water and leave it to cool.
Kitchen kit for this guide
Seafood prep and kitchen kit chosen to make the guide easier to use.
Common questions
- How do you kill a crab humanely before cooking?
- Current Seafish advice is not to boil a crab alive. Instead, put it in the freezer for 30 to 60 minutes to send it into a sleep-like torpor, then place it straight into boiling water.
- How long do you cook a crab?
- By weight: about 12-15 minutes for a 500g crab, 15-20 minutes up to 900g, 20-25 minutes up to 1.35kg, 25-30 minutes up to 3kg, then around 3 minutes per 500g for anything larger.
- How do you know when a crab is cooked?
- Go by the time-for-weight guide, then lift it out and let it cool. Take care not to overcook, which can make the meat stringy.
- Can you cook a crab in advance?
- Yes. Our advice is to cook it as soon as you get it, then keep the cooked crab in the fridge, where it will be good for a couple of days.
- Why must a crab be alive before cooking?
- Bacteria destroy the meat very quickly once a crab dies, so it should be cooked while alive or immediately after. A crab with limp claws and still antennae is close to death and should be cooked at once.
