Concentration Calculator: what this tool is for
The online chemical concentration converter and calculator provides accurate conversions between major concentration scales used across analytical chemistry, biology, and process engineering: molarity (mol/L), mass concentration (g/L), weight percentage (% w/w), parts per million (ppm), and normality (N).
Different scientific and industrial domains express concentrations in varying formats: molarity for reaction stoichiometry, mass concentration for regulatory compliance, mass percentage for commercial concentrated acids, or parts per million for environmental trace analysis.
The tool seamlessly accounts for critical physical parameters: solute molar mass M (auto-computed from formula), solution density ρ, and valence/equivalence factor z.
It also includes a direct calculation mode to determine all concentration units simultaneously from dissolved solute mass and solution volume.
All equivalents are displayed in an interactive correspondence table with one-click copy buttons for laboratory records and safety data sheets.
No file stored
Nothing is saved on our servers, during or after processing.
Local processing
The computation runs in your browser whenever the technology allows it.
Instant result
No waiting and no export queue: the result appears live.
Free, no account
No sign-up, no daily limit and no intrusive ads.
What this tool gives you
Comprehensive Multi-Unit Interconversions
Convert effortlessly between molarity (M, mM), mass concentration (g/L, mg/mL), weight percentage (% w/w), ppm, and normality without manual errors.
Accounts for Molar Mass and Density
Conversion algorithms rigorously incorporate chemical molar mass and solution specific gravity, eliminating approximations on concentrated solutions.
Real-Time Correspondence Matrix
Simultaneously view all equivalent expressions of your concentration value to prepare technical reports and safety documentation.
Direct Mass and Volume Calculation
Enter dissolved solute mass and total solution volume to instantly derive molarity, mass concentration, and ppm.
Real-world examples
Equivalence benchmarks for common laboratory reagents and analytical solutions.
Converting molarity to mass concentration
For a 0.5 mol/L sulfuric acid solution H2SO4 (M = 98.08 g/mol), the mass concentration is Cm = 0.5 mol/L × 98.08 g/mol = 49.04 g/L.
Converting environmental ppm to molarity
A dissolved lead Pb (M = 207.2 g/mol) concentration of 10 ppm (10 mg/L = 0.01 g/L) corresponds to a molarity C = 0.01 / 207.2 = 4.826 × 10⁻⁵ mol/L (48.26 µM).
How to use Concentration Calculator
Specify solute formula or molar mass
Type the chemical formula (e.g., H2SO4, NaCl) to compute its molar mass automatically, or enter the value directly in g/mol.
Set solution density and valence factor
For standard dilute aqueous solutions, keep density at 1.00 g/mL. For concentrated acids or bases, input the specific gravity from the bottle label.
Select input unit and enter value
Choose your known concentration unit (molarity, g/L, %, ppm, or normality) and type the value.
Review and copy equivalent values
The correspondence matrix instantly displays all equivalent concentration formats with copy buttons for each metric.
Tips and mistakes to avoid
Distinguish between % w/w and % w/v
% w/w (weight/weight) represents grams of solute per 100 g of total solution, while % w/v (weight/volume) represents grams of solute per 100 mL of solution.
1 ppm in dilute aqueous solution = 1 mg/L
In water and dilute solutions where density is ~1 kg/L, 1 part per million (ppm) exactly equals 1 mg of solute per liter of solution (1 mg/L = 1 g/m³).
Normality depends on reaction equivalents
Normality N = z × C depends on the reaction type: for sulfuric acid H2SO4 (diprotic acid, z = 2), a 1 M solution has a normality of 2 N.
Avoid : Ignoring density when converting weight percentages
Converting concentrated solutions (e.g., 37% HCl with density 1.19 g/mL) without density will result in a ~20% error in calculated molarity.
Avoid : Confusing ppm (parts per million) with ppb (parts per billion)
1 ppm equals 1,000 ppb. Double-check metric scaling factors when checking regulatory environmental limits.
Frequently asked questions
Answers to the questions people ask about Concentration Calculator.
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Updated on August 2026. See all tools