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Concentration Calculator — mg/mL & mcg/mL
Calculate solution concentration from mass and final volume. Convert milligrams or micrograms into mg/mL and mcg/mL, with the formula explained.
Mass concentration formula
Concentration (mg/mL) = mass (mg) ÷ final volume (mL)
For an arithmetic example, 12 mg in a final solution volume of 3 mL gives 4 mg/mL, or 4,000 mcg/mL. The conversion to micrograms uses the factor 1,000. Reference: NIST: Metric prefixes.
Use final volume, not an assumed volume
The denominator is the final solution volume. The amount of liquid added and final solution volume are not always identical. This tool assumes the mass is fully dissolved and evenly distributed; it does not check solubility, stability, purity, or preparation instructions.
Why does zero volume have no result?
Division by zero is undefined. Enter a positive final volume. A zero mass with a positive volume returns zero concentration.
Concentration is not a total amount
4 mg/mL describes the mass in each millilitre. A 3 mL container at that concentration contains 12 mg in total. To find a volume for an already specified mass, divide that mass by the concentration, using matching mass units.