Concentration Converter — mol/L, g/L, %, ppm, Molarity

Formulas

Molarity M = (mass concentration in g/L) / molar mass
g/L = M × molar mass
mg/L = g/L × 1000
% w/v = (g/100 mL) = (g/L) / 10
% w/w = (g/100 g solution) = (g/L) / (10 × density)
ppm ≈ mg/L (dilute aqueous)
ppb = ppm × 1000

Formula variables

Molar mass — grams per mole of the solute (g/mol).
Density — mass per unit volume of the solution (g/mL). For dilute aqueous solutions, ≈ 1.0 g/mL.
Molarity (M) — moles of solute per liter of solution.
Normality (N) — equivalents per liter, where equivalents = moles × n.

Worked Examples

Example 1: 1 M NaCl to g/L

Molar mass of NaCl = 58.44 g/mol.
g/L = 1 × 58.44 = 58.44.
Result: 1 M NaCl = 58.44 g/L.

Example 2: 5 g/L glucose to mM

Molar mass of glucose = 180.16 g/mol.
Molarity = 5 / 180.16 = 0.02775 M.
In mM: 27.75 mM.

Example 3: 0.9% w/v NaCl (saline) to mM

0.9 % w/v = 0.9 g per 100 mL = 9 g/L.
Molarity = 9 / 58.44 = 0.154 M = 154 mM.

Example 4: 100 mg/dL glucose to mM

100 mg/dL = 1 g/L.
Molarity = 1 / 180.16 = 0.00555 M = 5.55 mM.

Common Concentration Units

Concentration unit reference
Unit	Symbol	Meaning	Common use
Molarity	M (mol/L)	Moles per liter of solution	Chemistry
Millimolar	mM	10⁻³ mol/L	Biochemistry, medicine
Micromolar	µM	10⁻⁶ mol/L	Enzymology
Mass concentration	g/L, mg/L	Mass per volume	Biology, environment
% w/v	%	g per 100 mL	Medical IV solutions
% w/w	%	g per 100 g	Industrial chemistry
% v/v	%	mL per 100 mL	Alcoholic beverages
ppm	ppm	mg/L (dilute aqueous)	Water, atmosphere
ppb	ppb	µg/L (dilute aqueous)	Trace contaminants
Normality	N (eq/L)	Equivalents per liter	Acid-base titrations
Molality	m (mol/kg)	Moles per kg of solvent	Colligative properties

Common Molar Masses

Common molar masses
Compound	Formula	Molar mass (g/mol)
Water	H₂O	18.015
Sodium chloride	NaCl	58.44
Glucose	C₆H₁₂O₆	180.16
Sucrose	C₁₂H₂₂O₁₁	342.30
Hydrochloric acid	HCl	36.46
Sulfuric acid	H₂SO₄	98.08
Sodium hydroxide	NaOH	40.00
Potassium chloride	KCl	74.55
Calcium carbonate	CaCO₃	100.09
Ethanol	C₂H₅OH	46.07

Real-World Uses

Medical: IV solutions (% w/v), blood glucose (mg/dL ↔ mmol/L), drug concentrations.
Chemistry: Reaction calculations (molarity), titration (normality).
Environmental: Water quality (ppm, mg/L), air quality (ppb).
Pharmacology: Drug dosing (mg/mL, µg/mL).
Biology: Growth media (g/L), enzyme kinetics (µM).
Food science: Additive levels (ppm), alcohol content (% v/v).

Unit Definitions

Molarity (M)

The number of moles of solute per liter of solution. The most common concentration unit in general chemistry.

Mass concentration

The mass of solute per unit volume of solution. Common units are g/L, mg/mL, mg/dL, and µg/mL.

% w/v (mass/volume percent)

Grams of solute per 100 mL of solution. Used for medical IV solutions and pharmaceutical preparations.

% w/w (mass/mass percent)

Grams of solute per 100 g of solution. Used in commercial chemicals and industrial processes.

ppm and ppb

Parts per million and parts per billion. For dilute aqueous solutions, 1 ppm ≈ 1 mg/L and 1 ppb ≈ 1 µg/L.

Related Converters

Frequently Asked Questions

How do you convert molarity to g/L?

Multiply molarity by the solute's molar mass. For example, 0.1 M NaCl × 58.44 g/mol = 5.844 g/L.

How do you convert % w/v to molarity?

Multiply % w/v by 10 to get g/L, then divide by molar mass. For example, 0.9% w/v NaCl = 9 g/L ÷ 58.44 = 0.154 M.

Is ppm the same as mg/L?

For dilute aqueous solutions, yes. For other solvents or concentrated solutions, ppm is a mass ratio (mg/kg) that requires the solution density to convert to mg/L.

What is the difference between % w/v and % w/w?

% w/v (mass/volume) measures grams of solute per 100 mL of solution. % w/w (mass/mass) measures grams per 100 g of solution. They are numerically equal only when the solution density is 1.0 g/mL.

What is a normal solution?

A 1 N solution contains 1 gram-equivalent of solute per liter of solution. For HCl (monoprotic), 1 N = 1 M. For H₂SO₄ (diprotic), 1 N = 0.5 M.