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Molarity Calculator

Calculate molarity from normality, or solve for mass, volume, or molar mass using the standard formula.

💡 Quick Summary

Calculate molarity (mol/L) from normality and n-factor, or solve for molarity, mass of solute, volume of solution, or molar mass using the standard formula. Search 130+ laboratory compounds for automatic molar mass and n-factor lookup.

📋 How to Use

Choose a calculation mode using the tabs: From Normality converts a normal solution to molar, or From Standard Formula lets you solve for any one variable.
From Normality: Select a compound (auto-fills n-factor) or manually enter the n-factor. Enter the normality value and select its unit (N or mN). Click Calculate.
From Standard Formula: First select what you want to solve for using the "Solve For" radio buttons — that field will be disabled and marked ??.
Provide the molar mass by selecting a compound from the database or entering it manually (unless you are solving for molar mass).
Enter all other known values — mass of solute, volume of solution, and molarity — with their appropriate units. Click Calculate.
Click Reset to clear all fields and start again.

🧮 Formulas & Logic

Molarity (standard)

M = n / V = (mass(g) / MM) / V(L)

From Normality

M = N / n-factor

Solve for Mass

mass(g) = M × MM × V(L)

Solve for Volume

V(L) = mass(g) / (MM × M)

Solve for Molar Mass

MM = mass(g) / (M × V(L))

📊 Result Interpretation

mol/L (M) unit

Molarity is expressed as moles of solute per litre of solution (mol/L). A 1 M solution contains 1 mole of solute in exactly 1 litre of solution.

Molarity vs Molality

Molarity (M) uses solution volume; molality (m) uses solvent mass. Molarity changes slightly with temperature (volume expands), whereas molality is temperature-independent.

Normality relationship

Normality (N) = Molarity × n-factor. For HCl (n=1), N = M. For H&sub2;SO&sub4; (n=2), a 1 M solution is 2 N.

n-factor meaning

The n-factor (equivalence factor) is the number of reactive units per formula unit — protons donated by acids, electrons transferred in redox reactions, or equivalents for salts.

🔬 Applications

Preparing standard solutions for titrations and analytical chemistry
Converting between normality and molarity in acid-base and redox titrations
Pharmaceutical solution preparation and quality control
Calculating reagent quantities for cell culture media and buffers
Electrochemistry — calculating electrolyte concentrations
Dilution calculations (use with C&sub1;V&sub1; = C&sub2;V&sub2;)
Checking solution concentrations for industrial chemical processes

⚠️ Common Mistakes & Warnings

Volume is total solution volume, not solvent volume

Molarity uses the total volume of the final solution (solvent + dissolved solute). Do not enter the volume of pure solvent — that gives a slightly incorrect result. Always make up to the final volume in a volumetric flask.

Check the correct compound form

Hydrated and anhydrous salts have different molar masses (e.g. CuSO&sub4; vs CuSO&sub4;·5H&sub2;O). Select the exact form you are weighing to get an accurate result.

n-factor depends on reaction context

The n-factor of a compound is not always fixed — it can vary depending on the reaction. For example, KMnO&sub4; has n=5 in acidic medium but n=3 in neutral medium. The value in the database is the most common usage.

❓ Frequently Asked Questions

What is molarity?

Molarity (M) is the number of moles of solute dissolved per litre of solution. It is the most widely used concentration unit in chemistry. A 1 M NaCl solution contains 1 mole (58.44 g) of NaCl in every litre of solution.

How is molarity different from normality?

Normality (N) = Molarity × n-factor. For acids, the n-factor equals the number of ionisable protons: HCl has n=1 (N=M), H&sub2;SO&sub4; has n=2 (N=2M for complete ionisation). Normality is used in titration calculations where equivalent weights matter.

What is the n-factor?

The n-factor (equivalence factor) represents the number of reactive units per formula unit. For acids it is the number of H¹ ions donated, for bases the number of OH¹ ions donated, and for oxidising/reducing agents the change in oxidation state per formula unit.

Why does molarity change with temperature?

Molarity is volume-based. When temperature increases, the solution expands and volume increases, so the same mass of solute occupies more volume — molarity decreases slightly. This is why molality (mass-based) is preferred for thermodynamic calculations.

How do I make a 1 M NaCl solution?

Weigh 58.44 g of NaCl. Dissolve it in a small volume of distilled water, then transfer to a 1-litre volumetric flask and make up to the 1-litre mark. Do NOT add NaCl to 1 litre of water — that gives slightly more than 1 litre of solution and a slightly lower molarity.

What units does this calculator accept?

Mass: mg, g, or kg. Volume: mL or L. Molarity: mM (millimolar) or M. Normality: mN (millinormal) or N. The calculator handles all unit conversions automatically.