PeppyCalcTools
Home / Conversion tools / mM ↔ mg/mL
Free calculator

mM ↔ mg/mL Converter

Convert millimolar (mM) concentration to mg/mL — or convert mg/mL back to mM — using the substance's molecular weight.

What do I need?

Enter the concentration you already have, choose its unit, then enter the molecular weight (MW) in g/mol. Molecular weight is required because mM measures molecules while mg/mL measures mass.

Enter g/mol (numerically the same as Da for a single molecule).
—

Enter a concentration and molecular weight above.

Show the math

mM → mg/mL: mM × molecular weight ÷ 1000

mg/mL → mM: mg/mL × 1000 ÷ molecular weight

What does mM mean?

mM means millimolar, or millimoles per litre. It describes concentration by the number of molecules present. mg/mL describes concentration by mass per volume. Because different substances have different molecular weights, there is no universal mM-to-mg/mL conversion without knowing molecular weight.

Example

A 5 mM solution of a substance with a molecular weight of 500 g/mol is 2.5 mg/mL. The same calculation works in reverse: 2.5 mg/mL at MW 500 equals 5 mM.

Important

This tool performs concentration arithmetic only. Verify the molecular weight for the exact substance and form you are working with.