Molecular Weight Calculator
Calculate the molecular weight of a chemical compound from its formula.
Assumptions used in this calculation
- Formula format: Supports flat formulas with element symbols and counts (e.g. C6H12O6); nested parentheses like Ca(OH)2 are not supported.
About this calculator
Calculating a compound's molar mass by hand means looking up the atomic weight of every element in its formula, multiplying each by how many atoms of that element appear, and summing the results, a process that's easy to mess up on formulas with several elements or large atom counts, like glucose (C₆H₁₂O₆) or a hydrated salt. This calculator parses a chemical formula you type in (element symbols followed by their counts) and automatically looks up each element's standard atomic weight, multiplies it by the atom count, and sums everything to return the total molecular weight in grams per mole. It's the number you need before you can calculate molarity, dilute a solution to a target concentration, or convert between mass and moles for a stoichiometry problem, and doing it here in seconds avoids flipping through a periodic table and manually tracking a running total by hand.
Worked example
Water (H2O)
Result: 18.015 g/mol
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