Molar mass (M) is the mass of one mole of a substance, measured in grams per mole (g/mol). One mole contains 6.022 × 10²³ particles (Avogadro's number), so molar mass numerically equals the average mass of one particle in atomic mass units. This bridge between microscopic particles and macroscopic measurements is fundamental to quantitative chemistry.
The calculator parses chemical formulas using standard notation, identifying elements and their stoichiometric coefficients. Each element's contribution is calculated by multiplying its atomic mass (from IUPAC 2021 values) by its count in the formula. Parentheses and complex formulas are handled through recursive parsing. Mass percentages show each element's contribution to the total molecular weight.
Also known as the Law of Definite Proportions, this principle states that a given chemical compound always contains its component elements in fixed ratio and does not depend on its source and method of preparation. For example, water (H₂O) is always 11.2% hydrogen and 88.8% oxygen by mass, whether it comes from a tap, a river, or a laboratory reaction.
