# Molecular Weight Calculator Calculate molar mass, elemental composition, and mass percentages from a chemical formula > Canonical page: https://elysiatools.com/en/tools/molecular-weight-calculator - **Category:** Math & Numbers - **Keywords:** molecular weight, molar mass, chemical formula, stoichiometry, chemistry ## Overview The Molecular Weight Calculator computes the molar mass, elemental composition, and mass percentages of any chemical formula. Simply input a formula, including hydrates or complex compounds, to instantly retrieve precise molecular weights and stoichiometric details. ## Inputs - **Chemical Formula** (text): CuSO4·5H2O - **Decimal Places** (number) ## When to use - When preparing chemical solutions in a laboratory and needing to calculate the exact mass of a solute required for a specific molarity. - When analyzing stoichiometry problems to determine theoretical yields or mass percentages of individual elements in a compound. - When verifying the molecular weight of complex chemical formulas, including hydrates with dot notation. ## How it works - Enter the chemical formula (e.g., CuSO4·5H2O) into the input field. - Specify the desired number of decimal places for the calculation precision. - The tool parses the formula, identifies the constituent elements, multiplies their atomic weights by their quantities, and outputs the total molar mass. ## Use cases - Calculating the molar mass of complex hydrates for laboratory reagent preparation. - Determining the mass percentage of specific elements within a compound for stoichiometric analysis. - Verifying chemical formulas and molecular weights during academic study or research. ## Frequently asked questions ### Does the calculator support hydrates? Yes, you can input hydrates using dot notation, such as CuSO4·5H2O. ### How does the tool handle parentheses in formulas? It parses nested parentheses, multiplying the subscripts outside the parentheses by the elements inside. ### Can I adjust the precision of the output? Yes, you can set the decimal places option to any value between 0 and 8. ### What atomic weights does the calculator use? It uses standard IUPAC atomic weights for all elements on the periodic table. ### Is case sensitivity important when entering formulas? 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