Molarity
M = n / VLast updated:
Molarity Calculator
Calculate molarity, moles, and volume for chemical solutions. Prepare accurate lab solutions with dilution formulas. Free chemistry concentration calculator.
Molarity Calculator
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Calculate solution concentration using M = n/V
M = n / V
Molarity = Moles ÷ Volume (in Liters)
Common Molarities
Household vinegar:~0.8 M
Stomach acid:~0.1 M
Seawater (NaCl):~0.5 M
Blood glucose:~0.005 M
Enter values above to see results.
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Solution Chemistry
Molarity Calculator: Solution Concentration Guide
Prepare precise molar solutions, perform dilutions, and convert between mass and concentration for lab and industrial use.
Formula
M = n / V
Dilution
C₁V₁ = C₂V₂
Unit
mol/L (M)
Volume
Solution, not solvent
Reviewed by: CalculatorApp Chemistry & Engineering Team
What Is Molarity?
Molarity is the fundamental unit of solution concentration in chemistry. It links the number of moles of dissolved substance to the total volume of solution, enabling precise and reproducible lab work: buffer preparation, titration standards, drug dosing calculations, and industrial chemical process design all depend on accurate molar concentrations.
Moles from M
n = M × VMass of solute
m = M × V × MᵣDilution
C₁V₁ = C₂V₂| Concentration Range | Classification | Typical Use |
|---|---|---|
| < 0.1 M | Dilute | Trace analysis, physiological solutions |
| 0.1 – 1 M | Working concentration | Lab buffers, reagent solutions |
| 1 – 10 M | Concentrated | Stock solutions, industrial reagents |
| > 10 M | Highly concentrated | Fuming acids, electrolyte concentrates |
History Timeline
1811: Avogadro proposes equal volumes of gas contain equal numbers of molecules.
1834: Faraday introduces equivalents for electrochemical work.
1860: Cannizzaro unifies atomic and molecular weight concepts at Karlsruhe.
1887: Arrhenius and Ostwald formalize solution theory and ion activities.
1900s: Molarity standardized as the primary concentration measure in analytical chemistry.
Modern era: IUPAC formally defines molarity and maintains SI-consistent concentration units.
PubMed Chemistry
Peer-reviewed solution chemistry and pharmacology research.
WHO Chemical Safety
International chemical safety and exposure guidelines.
CDC ATSDR
Toxicological profiles for industrial chemicals in solution.
NIST WebBook
Physical and chemical data for standard compounds.
Myth: Molarity and molality are the same.
Fact: Molarity depends on volume (affected by temperature); molality depends on solvent mass (temperature-independent).
Myth: Volume of solvent equals volume of solution.
Fact: The solution volume includes solute, which displaces solvent volume.
Myth: 1 M means 1 gram per liter.
Fact: 1 M means 1 mole (= molar mass in grams) per liter of solution.
Myth: Diluting by half doubles concentration.
Fact: Diluting by half halves concentration; use C₁V₁ = C₂V₂ to be precise.
FAQ (12)
What is molarity?
Molarity (M) is the number of moles of solute dissolved per liter of solution, expressed in mol/L.
How is molarity different from molality?
Molarity uses volume of solution (L); molality uses mass of solvent (kg). Temperature affects molarity but not molality.
What is the dilution formula?
C₁V₁ = C₂V₂ — the moles of solute stay constant when you add more solvent to dilute a solution.
What are standard lab concentrations?
1 M is common for stock solutions; physiological saline is 0.154 M NaCl; blood glucose is ~5 mM.
Can I use molarity for any solute?
Yes, for any soluble compound. Use molar mass to convert grams to moles before calculating.
How do I prepare a 1 M solution?
Dissolve one mole of solute (in grams = molar mass) in enough water to total 1 liter of solution.
Do temperature changes affect molarity?
Yes. Higher temperatures expand volume slightly, decreasing molarity. Use molality for temperature-sensitive work.
What is normality vs. molarity?
Normality = molarity × equivalents per mole; useful for acid-base and redox titrations.
How precise should my volume measurement be?
Use a volumetric flask for primary standards; graduated cylinders introduce more error.
What if my solute is a hydrate?
Use the full molar mass including water of crystallization when weighing hydrated salts.
What is parts per million (ppm) relation?
For dilute aqueous solutions, 1 ppm ≈ 1 mg/L ≈ μM range; use molarity for stoichiometric calculations.
Can this apply to gas concentration?
Gas concentrations are usually expressed in mol/L at given T/P but ideal gas law is typically preferred.
References
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