How many milliliters of liquid in a drop depends on the device that holds the liquid. Another common clinical device used to hold fluid is the infusion set used for intravenous infusion, where one drop is equal to 0.04 ml, or 0.05 ml and 0.06 ml on average. Because infusion sets come in different sizes, the algorithm varies from one infusion set to another. For example, a regular disposable infusion set is the same as a drip tube, 20 drops add up to 1ml; a precision infusion set has a larger drop, 15 drops are 1ml; a children’s infusion set for children requires a slower drip rate, so the drop is the smallest, 60 drops add up to 1ml. different infusion sets, the number of ml for a drop will also vary, as will the medication added inside the infusion, after the medication is added.