Fill a large pot with water. Add 2 tablespoons of salt to each quart of water.
A good rule of thumb is to allow 2 1/2 quarts of water per lobster. Bring water to a hard boil and place lobster in boiling water and cover.
Once the water returns to a boil, time 1- 1 1/2 lb hard shelled lobster for 15 minutes and over 1 1/2 lbs for 18-20 minutes. Reduce the time for new or soft shelled lobsters by approximately 3 minutes.
Generally, if the antennae pulls out easily then the lobster is done.