- Is 1 mg the same as 1 ml?
So, a milligram is a thousandth of a thousandth of a kilogram, and a milliliter is a thousandth of a liter. Therefore, there must be 1,000 milligrams in a milliliter, making the formula for mg to ml conversion: mL = mg / 1000 .

- What does 15 mg/ml mean?
Milligrams per milliliter (mg/mL) is a measurement of a solution's concentration. In other words, it's the amount of one substance dissolved in a specific volume of a liquid. To find the concentration of a solution, divide the dissolved mass by the volume of the solution.