approximately 1.2-1.5 gallons ( 5 liters )
adult will have approximately 1.2-1.5 gallons (or 10 units) of blood in their body. Blood is approximately 10% of an adult's weight.
We only have 1.5 gallons of blood in our body?! That’s not a lot. But at the same time, it’s 1 and a half milk jugs, and 1 milk jug is huge.