Find a compound's molar mass

The job

Stoichiometry starts with molar mass: grams per mole of a compound. Looking up each element and multiplying by subscripts is exactly the kind of arithmetic that benefits from a calculator.

Enter a formula

Type standard notation — H2O, Ca(OH)2, Fe2(SO4)3 — with parentheses for groups and hydrates written as CuSO4·5H2O or CuSO4.5H2O. The result shows total g/mol and each element's contribution.

• Nested parentheses work: K4[Fe(CN)6] style bracketed complexes parse fine.
• Charges like Fe3+ or SO4 2− are stripped — the mass of the lost electron is negligible anyway.

Worked example

CuSO4·5H2O (blue vitriol): 63.546 + 32.06 + 4×15.999 + 5×18.015 ≈ 249.68 g/mol. So a 0.1 mol solution needs 24.97 g — the breakdown shows the five waters contribute 90 g of it.

Where it stops

Standard atomic weights — no isotope-specific masses (use ¹⁸O water? this won't match), no polymer repeat-unit shorthand like –CH2–. Elements beyond Og aren't recognized; typos like 'Hf' vs 'HF' return a parse error rather than a guess.