Glucose
Input C6H12O6
Output Molar mass 180.156 g/mol and mass % for C, H, and O
Molecular Weight Calculator (Formula to Molar Mass and Elemental Composition)
Calculate molar mass and elemental composition by mass from a chemical formula such as C6H12O6.
Supports parentheses and hydrates such as CuSO4·5H2O, and warns instead of silently guessing when notation is ambiguous.
Show g/mol and Da together
Supports parentheses, brackets, and hydrates
Reuse with copy, CSV, and shareable URLs
How to use
- Enter a chemical formula or choose one of the example chips.
- Adjust significant digits, atomic weight table, or ASCII '.' handling if needed.
- Run the calculation to see molar mass, interpreted formula, and elemental composition by mass.
- Reuse the result with copy, CSV export, or a shareable URL.
Sample
Copper(II) sulfate pentahydrate
Input CuSO4·5H2O
Output Molar mass, interpreted formula CuSO4 + 5H2O, and elemental composition
Ambiguous ASCII dot
Input CuSO4.5H2O
Output Shows a warning and the interpretation used for this run
Glossary
Molecular weight
The sum of the atomic masses in a chemical formula.
Molar mass
The mass per mole of a substance. This tool displays it in g/mol.
Elemental composition
The fraction of the total mass contributed by each element, expressed as mass percent.
Hydrate
A compound that contains water of crystallization, written like CuSO4·5H2O.
Formulas
- Total mass = Σ(count of each species × atomic weight used)
- Mass % = contribution mass ÷ total mass × 100
Notes
- Charge notation does not affect mass and is ignored in the calculation.
- ASCII '.' is ambiguous, so use '·' for hydrates whenever possible.
- Reaction balancing and stoichiometric yield calculations are outside the scope of this tool.
FAQ
Does it support parentheses and hydrates?
Yes. It supports common parentheses, bracketed groups, and hydrate notation such as CuSO4·5H2O. Because ASCII '.' can look like either a decimal point or a hydrate separator, the tool shows a warning and the interpretation it used.
Which atomic weights does it use?
The result always shows the selected atomic weight table and its version. A shareable URL preserves the calculation settings, including the table used.
Is molecular weight different from molar mass here?
In this tool they are treated as the same numerical value and displayed with both g/mol and Da labels.
Can I use it for reaction equations?
This tool is focused on formula-based molar mass and composition. For reaction coefficients, limiting reagent checks, or yield calculations, use the stoichiometry calculator.
Can I specify isotopes?
Yes. Turn on isotope notation in Settings to use inputs such as [13]C. By default the tool uses representative atomic weights.