Science · Chemistry / Lab

Molarity Calculator

Work out molarity, moles, volume or the mass of solute you need to weigh out. Molar mass is entered directly or picked from a quick reference list.

M = n/V    n = mass / Mr
Solve for:
Molar mass Mr
M · molarity
n · moles
V · volume
Mass of solute
Solved value
M—
Concentration definitions
M = n/V    n = mass/Mr    mass = M·V·Mr
Molarity M is moles of solute per litre of solution. To make a solution, convert the target moles to a mass using the molar mass, weigh it out, dissolve, then top up to the final volume — not the other way around, because volume changes slightly as solute dissolves.

🔢 Four-way solver

Solve for molarity, moles, volume or the mass to weigh out.

🧪 Quick chemicals

One click fills the molar mass of common lab reagents.

🔩 Lab units

M / mM / μM, mol / mmol, mL / L and g / mg / kg convert.

📈 Worked steps

See the full chain: moles → mass → concentration.

More solution chemistry

Dilution uses molarity directly with C₁V₁ = C₂V₂.

Dilution Calculator

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