How Much Blood Can You Lose before You Die?
An adult can typically lose around 40 percent of his blood. The average adult body contains 8 to 10 pints of blood, so it can safely lose between 3.2 and 4 pints, but no more.
The amount of blood an average sized person can lose before death is approximately three liters or 25 to 35 percent of their total blood volume.
The body typically contains 14-18 pints of blood. If a person would lose 3-4 pints of blood, they would die.
Anything more than a 40 percent loss of blood is considered a Class IV hemorrhage and is very possibly fatal. An average transfusion takes almost 3 1/2 pints of blood.