What is molar mass and how is it calculated?

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It's calculated by summing the atomic masses of all atoms in a chemical formula. For example, water (H₂O) has a molar mass of (2 × 1.008) + 15.999 = 18.015 g/mol. Our calculator automates this using the latest atomic mass data from the periodic table.

Why is molar mass important in chemistry?

Molar mass serves as a bridge between the microscopic world of atoms/molecules and measurable laboratory quantities. It's essential for: converting between grams and moles, preparing solutions with specific concentrations, calculating stoichiometric amounts in chemical reactions, determining empirical and molecular formulas, and analyzing experimental data in quantitative chemistry.

How do you calculate molar mass from a chemical formula?

To calculate molar mass: 1) Identify all elements in the formula, 2) Count the atoms of each element, 3) Multiply each element's atomic mass by its atom count, 4) Sum all these values. For compounds with parentheses, multiply everything inside by the subscript outside. Hydrates include water molecules in the calculation (e.g., CuSO₄·5H₂O).

What's the difference between atomic mass and molar mass?

Atomic mass (atomic weight) is the average mass of an atom of an element, measured in atomic mass units (amu). Molar mass is the mass of one mole (6.022×10²³ entities) of a substance, measured in grams per mole. Numerically, they're equal—carbon's atomic mass is 12.01 amu, and its molar mass is 12.01 g/mol—but the units and conceptual meanings differ.

How accurate are online molar mass calculators?

Quality molar mass calculators are highly accurate when they use current IUPAC atomic weight values (which include isotopic abundance data). Accuracy depends on the precision of the atomic mass data and proper handling of chemical formulas. For most educational and laboratory purposes, these calculators provide sufficient precision. For extremely precise work, consult the latest IUPAC technical reports.

Molar Mass Calculator

Calculate the molecular weight of any chemical compound by entering its formula

🧪 Chemical Formula Input

Chemical Formula

Decimal Precision

📚 Formula Notation Guide

Element Count Notation

Use numbers to indicate atom counts

Supported Formats:

• Simple formulas: H2O, CO2, NaCl
• Complex formulas: C6H12O6, Al2(SO4)3
• Parentheses: Mg(OH)2, (NH4)2SO4
• No subscripts needed: Use regular numbers

📊 Molar Mass Results

                            Molar Mass
                            18.02 g/mol
                        

Formula H2O

Total Atoms 3

Elements 2

Elemental Composition

Element	Count	Atomic Mass	Contribution	Percentage

🔍 Formula Analysis

Formula Type Molecular

Charge Neutral

Mass Precision ±0.01 g/mol

Validation Valid

⚖️ What is Molar Mass?

Molar mass is the mass of one mole of a substance, measured in grams per mole (g/mol). It’s calculated by summing the atomic masses of all atoms in a chemical formula.

M = Σ(n × atomic mass)

Sum of (atom count × atomic mass) for all elements

Example: H2O = (2×1.008) + (1×16.00) = 18.02 g/mol

Water molar mass calculation

🧪 Applications

Molar mass calculations are essential for:

✓ Stoichiometric calculations
✓ Solution preparation
✓ Chemical reaction balancing
✓ Analytical chemistry
✓ Pharmaceutical dosing
✓ Material science

n = m / M

Moles = Mass ÷ Molar Mass

🔬 Common Formulas

Important chemical compounds and their molar masses:

• Water: H2O = 18.02 g/mol
• Table Salt: NaCl = 58.44 g/mol
• Glucose: C6H12O6 = 180.16 g/mol
• Carbon Dioxide: CO2 = 44.01 g/mol
• Sulfuric Acid: H2SO4 = 98.08 g/mol
• Ammonia: NH3 = 17.03 g/mol

About Our Chemistry Tools

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Our team of chemistry specialists and educators develops and maintains these precise calculation tools for students, researchers, laboratory professionals, and anyone working with chemical measurements and conversions.

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These chemistry conversion tools are for informational, educational, and reference purposes only. They should not replace proper laboratory procedures, safety protocols, or professional chemical analysis. Always follow appropriate safety measures when working with chemicals.

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