Molecular Weight Calculator
Enter any chemical formula to get molar mass, percent composition, and a grams-to-moles conversion. Supports nested groups and hydrates.
C6H12O6 — 3 distinct elements
1 g = 0.0056 mol
Elemental composition
| Element | Atoms | Mass (g/mol) | % of total |
|---|---|---|---|
| O | 6 | 95.994 | 53.28% |
| C | 6 | 72.066 | 40.00% |
| H | 12 | 12.096 | 6.71% |
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Method notes
Uses IUPAC conventional standard atomic weights. Monoisotopic mass is not the same as average molar mass — use monoisotopic values for mass-spec work.
How to calculate molecular weight
The formula
Molar mass is the sum of every atom's standard atomic weight. For glucose (C6H12O6): 6 × 12.011 + 12 × 1.008 + 6 × 15.999 = 180.156 g/mol.
Grams to moles
Moles = mass (g) ÷ molar mass (g/mol). This is the first step for almost every buffer, stock, and reaction calculation at the bench.
Hydrates
Write hydrates with a dot: CuSO4·5H2O. Waters of crystallization count toward molar mass, so ignoring them biases every stock you make.
Nested groups
Parentheses and brackets multiply everything inside them: Ca(OH)2 and K3[Fe(CN)6] both parse correctly.
What Quandra v8 adds
These calculators give you one number at a time. Quandra v8 writes the statistical analysis plan, generates R/SAS code, cross-checks assumptions against a locked reference corpus, and keeps an audit trail for regulated work.