Calculate molarity, moles, or volume for a solution using M = n/V, or determine mass from molar mass, with support for mM, μM, and nM concentrations.
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Molarity (M)
1 M
Molarity (M)
1.000000
Moles (mol)
1.000000
Volume (L)
1.000000
Mass (g)
58.4400
Science — Chemistry
Molarity (M) is the most common measure of solution concentration in chemistry, defined as moles of solute per litre of solution: M = n/V. It appears in stoichiometry calculations, buffer preparation, titration analysis, and pharmaceutical formulation. This calculator solves for molarity, moles, volume, or mass when the other values are known.
To prepare 500 mL of a 0.1 M NaCl solution (molar mass 58.44 g/mol): moles needed = 0.1 × 0.5 = 0.05 mol; mass = 0.05 × 58.44 = 2.922 g. Dissolve 2.922 g NaCl in enough water to make up to 500 mL total volume. The calculator handles all four rearrangements: M = n/V, n = MV, V = n/M, and m = n × Mw.
Biochemistry routinely works with millimolar (mM = 10⁻³ M) and micromolar (μM = 10⁻⁶ M) concentrations. Drug plasma levels are often in nanomolar (nM = 10⁻⁹ M). The calculator accepts input and displays results in any of these units. A 1 μM solution of a drug with molar mass 500 g/mol contains only 0.5 μg/mL — the mass-from-moles output makes this visible.
Frequently asked questions
Molarity (M) is moles of solute per litre of solution — it depends on temperature because solution volume changes with temperature. Molality (m) is moles of solute per kilogram of solvent — it is temperature-independent. For temperature-sensitive work (e.g. boiling point elevation), molality is more precise.
Molar mass is the sum of atomic masses of all atoms in the molecular formula, found on the periodic table. For NaCl: Na (22.99) + Cl (35.45) = 58.44 g/mol. For H₂SO₄: 2 × 1.008 + 32.06 + 4 × 16.00 = 98.08 g/mol. Online databases like PubChem or ChemSpider list molar masses for most compounds.
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