Molarity, Mass & Volume Online Calculator — Solve for Concentration, Volume, or Mass

The core relationship used in solution preparation:

Mass (g) = Concentration (mol/L) × Volume (L) × Molecular Weight (g/mol)

Know any two of the three variables and solve for the third. The tool handles unit conversion automatically — no more counting decimal places.

Common pitfalls:

• Use the molecular weight for the correct salt form. Many reagents are supplied as hydrochlorides, sodium salts, or hydrates — their formula weights differ substantially from the free base. Always read the FW from the bottle label, not from a database entry for the parent compound.
• Hydrated reagents (e.g., CuSO₄·5H₂O) must use the hydrated formula weight; using the anhydrous MW gives a lower actual concentration than intended.
• Solubility limits. A calculation says you can make it — that doesn’t mean it will dissolve. DMSO stock solutions are typically 10–100 mM; for poorly water-soluble compounds, check solubility before you start.
• Proteins and antibodies are typically specified in mg/mL, not mol/L. Converting requires an accurate molecular weight; glycosylation can make the actual MW higher than the theoretical value.