Molarity Calculator

Calculate molarity, moles, or volume for chemical solutions. Essential tool for chemistry students, researchers, and laboratory professionals.

Molarity Calculation

Calculate

Number of Moles (n)

mol

Volume of Solution (V)

Common Compounds

Results

0.1

Concentration Units

Molarity (M):0.1 M

Millimolar (mM):100 mM

Micromolar (μM):100000 μM

Normality (N)*:0.1 N

*Assuming monovalent compound

Concentration Reference

Physiological saline: 0.9% NaCl ≈ 0.154 M

Seawater: ~0.6 M NaCl equivalent

Concentrated HCl: ~12 M (37% by weight)

Concentrated H₂SO₄: ~18 M (98% by weight)

Blood glucose: ~5 mM (normal fasting)

How to Use the Molarity Calculator

Step-by-Step Instructions

Select the calculation type from the dropdown menu
Enter the known values in the appropriate fields
Choose the correct units for each measurement
View the calculated result and additional information
Use common compound presets for quick calculations

Calculation Types

Molarity: Calculate concentration from moles and volume
Moles: Calculate amount from molarity and volume
Volume: Calculate volume from molarity and moles
Dilution: Calculate dilution parameters using M₁V₁ = M₂V₂
Mass to Molarity: Convert mass to molarity
Percent to Molarity: Convert percentage to molarity

Chemistry Formulas and Concepts

Fundamental Formulas

Molarity Formula:
M = n / V
Where M = molarity (mol/L), n = moles, V = volume (L)

Moles from Mass:
n = m / MW
Where n = moles, m = mass (g), MW = molecular weight (g/mol)

Dilution Formula:
M₁V₁ = M₂V₂
Initial molarity × initial volume = final molarity × final volume

Percent to Molarity:
M = (% × ρ × 10) / MW
Where % = percentage, ρ = density (g/mL), MW = molecular weight

Key Concepts

Molarity (M): Number of moles of solute per liter of solution. Most common concentration unit in chemistry.

Molality (m): Moles of solute per kilogram of solvent. Temperature-independent concentration unit.

Normality (N): Number of equivalent weights per liter of solution. Depends on the reaction.

Parts per million (ppm): Mass of solute per million parts of solution. Used for very dilute solutions.

Example Calculations

Example 1: NaCl Solution

Given: 5.84 g NaCl in 500 mL solution

Find: Molarity

Calculation:

Moles = 5.84 g ÷ 58.44 g/mol = 0.1 mol

Volume = 500 mL = 0.5 L

Molarity = 0.1 mol ÷ 0.5 L = 0.2 M

Result: 0.2 M NaCl solution

Example 2: Dilution

Given: 10 mL of 1 M HCl, dilute to 0.1 M

Find: Final volume needed

Calculation:

M₁V₁ = M₂V₂

1 M × 10 mL = 0.1 M × V₂

V₂ = 10 ÷ 0.1 = 100 mL

Result: Dilute to 100 mL total volume

Frequently Asked Questions

What's the difference between molarity and molality?

Molarity (M) is moles of solute per liter of solution, while molality (m) is moles of solute per kilogram of solvent. Molarity changes with temperature, but molality doesn't.

How do I prepare a solution from a solid compound?

Calculate the required mass using the molarity formula, weigh the compound, dissolve in less than the final volume, then dilute to the exact final volume in a volumetric flask.

What is the dilution formula M₁V₁ = M₂V₂?

This formula states that the number of moles before and after dilution remains constant. It's used to calculate how much solvent to add when diluting solutions.

How do I convert between different concentration units?

Use the appropriate conversion factors and formulas. For example, to convert from percentage to molarity, you need the solution density and molecular weight of the solute.