A person can lose up to 40% of his total blood volume without being in serious danger. This is due to the fact that our body can compensate for blood loss as long as this figure is not exceeded. There are actually four classes of blood loss or hemorrhaging. The first three classes range from 15% to 40% blood loss. The fourth class describes blood loss of greater than 40%. For a person who weighs 80 kilograms, this would be more than 2.24 liters of blood. Without immediate medical attention, a person in this state can lose his life.