numvana

Molarity (Molar Concentration) Calculator

Solve for molarity, mass of solute, or solution volume from any two of the three, via M = (mass ÷ molar mass) ÷ volume.

Molarity (M)
0.2 mol/L
Mass of solute
5.844 g
Solution volume
0.5 L
Moles of solute
0.1 mol

How it works

Molarity (molar concentration) is the number of moles of solute dissolved per liter of solution, M = n / V. The number of moles itself comes from mass divided by the solute's molar mass, n = mass / molarMass — so combined, molarity = (mass ÷ molar mass) ÷ volume. Given the molar mass and any two of {mass, volume, molarity}, this calculator rearranges that same identity to solve for whichever one you leave as the target.

The default values work out the classic example of dissolving table salt (NaCl, molar mass 58.44 g/mol): 5.844 g in 0.5 L of water gives exactly 0.1 mol, or a 0.2 mol/L (0.2 M) solution.

Units are kept in the standard chemistry convention throughout — grams, liters, and moles — rather than offering a metric/imperial toggle, since lab solutions are essentially always measured this way regardless of which country the recipe comes from.

FAQ

How do I find a compound's molar mass?

Add up the standard atomic weights of every atom in its formula (found on any periodic table) — for NaCl, that's sodium (~22.99) plus chlorine (~35.45), giving ~58.44 g/mol. This calculator takes molar mass as a direct input rather than computing it from a chemical formula, since that would require a hardcoded table of atomic weights rather than pure computation from what you supply.

Why does the calculator ask for volume in liters, not milliliters?

Molarity is defined per liter (mol/L), so liters is the unit the formula is calibrated for. If your target volume is in milliliters, divide by 1000 first — 250 mL is 0.25 L.

Related calculators