Question: how much blood do babies and children have?

Tat Ming Mako Ng answered on 24 Jun 2015:

It depends on how heavy they are. On average, we have 77 ml of blood per kg we weigh, so a 20 kg children will have 20 x 77 = 1 540 ml (1.54 litre) of blood, while a 5 kg baby will only have 5 x 77 = 385 ml of blood. Females generally have slightly less blood than males too.