Converting mg to ml is a two-step process that depends on the density of the substance in question. To do the conversion, you need to know the substance's density in mg/ml. The formula to use is:
Milligrams (mg) / Density (mg/ml) = Milliliters (ml)
For example, if you have a substance with a density of 0.8 mg/ml and you want to convert 500 mg to ml:
500 mg / 0.8 mg/ml = 625 ml
So, 500 milligrams is equal to 625 milliliters for a substance with a density of 0.8 mg/ml.