Molarity Calculator
Calculate molarity, moles, or volume for solutions (M = mol/L)
Calculator
M = n / V = 1 mol / 1 L = 1.0000 M
Molarity Formulas
- M = n / V (mol/L)
- n = M × V (moles)
- n = m / MW (moles from mass)
- m = n × MW (mass from moles)
- 1 M = 1 mol/L = 1 mmol/mL
How to Use
Calculate molarity, moles, or volume for solutions
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Input mass/moles and volume to find molarity
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See molarity with preparation instructions
Molarity Formula
M = mol / L
Molarity equals moles of solute divided by liters of solution.
Frequently Asked Questions
Molarity (M) is a measure of solution concentration - the number of moles of solute per liter of solution. A 1M solution has 1 mole of solute dissolved in enough solvent to make 1 liter total. It is the most common concentration unit in chemistry labs.
Moles = mass (g) divided by molar mass (g/mol). The molar mass is found by adding atomic masses from the periodic table. For NaCl: Na (23) + Cl (35.5) = 58.5 g/mol. So 117g of NaCl = 117/58.5 = 2 moles.
Molarity (M) is moles per liter of solution. Molality (m) is moles per kilogram of solvent. Molarity changes with temperature (volume changes), while molality stays constant. Molarity is more practical for lab work; molality for thermodynamic calculations.
Calculate needed mass: grams = Molarity x Volume(L) x Molar mass. For 500mL of 0.5M NaCl: 0.5M x 0.5L x 58.5g/mol = 14.6g. Dissolve 14.6g NaCl in water and add water until total volume is 500mL.