🧪 Concentration Calculator
Calculate solution concentration with three powerful tools in one. Compute molarity (M) from mass or moles, calculate mass percent (% w/w, % w/v, % v/v), and perform dilution calculations (C₁V₁ = C₂V₂) with step-by-step solutions and visual charts.
What Is Solution Concentration?
Solution concentration describes the amount of solute dissolved in a given amount of solvent or solution. It is a fundamental concept in chemistry, biology, and environmental science. This calculator supports three of the most common concentration expressions:
- Molarity (M): Moles of solute per liter of solution (mol/L). The most widely used concentration unit in chemistry.
- Mass Percent: The mass of solute as a percentage of the total solution mass (w/w), mass per volume (w/v), or volume per volume (v/v).
- Dilution: The process of reducing concentration by adding solvent, governed by the equation C₁V₁ = C₂V₂.
How to Use This Calculator
Select the calculation mode using the tabs at the top:
- Molarity: Calculate molarity from mass or moles, or find the mass needed to prepare a solution of target molarity.
- Mass Percent: Compute % w/w, % w/v, or % v/v by providing any two of percent, solute amount, or solution amount.
- Dilution: Solve for any missing variable in the C₁V₁ = C₂V₂ equation.
Why Use This Concentration Calculator?
- All-in-One: Three essential concentration tools in one calculator.
- Step-by-Step: See the exact calculation broken down for each mode.
- Visual Charts: Understand your results with bar charts and gauges.
- Free & Private: No registration, no data storage.
❓ Concentration Calculator FAQ
What is molarity?
Molarity (M) is the number of moles of solute per liter of solution. It is the most common unit of concentration in chemistry, expressed as mol/L.
What is the formula for molarity?
The formula is M = n / V, where n is moles of solute and V is volume in liters. If you have mass instead of moles, first calculate n = m / MW.
What is the difference between % w/w, % w/v, and % v/v?
% w/w uses solute mass divided by solution mass (both in grams). % w/v uses solute mass (g) divided by solution volume (mL). % v/v uses solute volume (mL) divided by solution volume (mL).
What is the dilution equation?
The dilution equation is C₁V₁ = C₂V₂, where C₁ and V₁ are the initial concentration and volume, and C₂ and V₂ are the final concentration and volume.
How do I calculate the mass needed to make a molar solution?
Use the formula m = M × V × MW, where M is the target molarity, V is volume in liters, and MW is molar mass in g/mol.
Can I enter volume in mL?
Yes. The molarity calculator automatically converts mL to L. Mass percent calculators use mL directly for w/v and v/v calculations.
What is the molar mass of a compound?
Molar mass is the sum of the atomic masses of all atoms in a chemical formula, expressed in grams per mole (g/mol). For example, NaCl has a molar mass of 58.44 g/mol.
How do I prepare a dilution from a stock solution?
Use the dilution calculator: enter the stock concentration (C₁), the volume of stock you want to use (V₁), and your target final volume (V₂). The calculator will find the final concentration (C₂).
What is the difference between molarity and molality?
Molarity (M) is moles of solute per liter of solution. Molality (m) is moles of solute per kilogram of solvent. Molality is temperature-independent because it uses mass rather than volume.
Can I convert between different concentration units?
This calculator focuses on molarity, mass percent, and dilution. To convert between other units like molality, ppm, or mole fraction, you would need additional density information.
What is a stock solution?
A stock solution is a concentrated solution that is diluted to a lower concentration for use in experiments. Dilution calculations use stock concentration (C₁) to determine how much is needed.
How accurate is this calculator?
This calculator uses standard formulas and provides results to the precision you select. For exact scientific work, consult current IUPAC values and use calibrated laboratory equipment.
Is this calculator free?
Yes, this calculator is completely free to use. No registration or personal data storage is required. All calculations are performed in your browser.
What does % w/v mean in practice?
% w/v is grams of solute per 100 mL of solution. For example, a 5% w/v NaCl solution contains 5 grams of NaCl in 100 mL of total solution. It is a common lab shorthand.
What is the difference between solute and solvent?
The solute is the substance being dissolved (e.g., salt). The solvent is the substance doing the dissolving (e.g., water). Together they form a solution.