🧬 Molecular Weight Calculator
Enter a chemical formula to obtain molar mass, elemental breakdown, and supporting stoichiometric data.
Supports parentheses, hydration dots (·), and stoichiometric prefixes like 5H2O.
Molar Mass
180.156 g/mol
Unique Elements
3
Total Atoms
24
Elemental Breakdown
| Element | Atoms | Atomic Mass (g/mol) | Contribution (g/mol) | Percent by Mass |
|---|---|---|---|---|
| C | 6 | 12.011 | 72.066 | 40.002% |
| H | 12 | 1.008 | 12.096 | 6.7142% |
| O | 6 | 15.999 | 95.994 | 53.2838% |
How to Use This Calculator
Enter the chemical formula
Use standard notation with element symbols (capital letter optionally followed by lowercase). Include parentheses for groups and dots for hydrates.
Check for parsing errors
If the formula cannot be parsed, an error message indicates the issue (such as mismatched parentheses or unknown symbols).
Review molar mass and percentages
The calculator lists each element's atom count, atomic mass, contribution, and percent by mass. Values update instantly as you edit the formula.
Use results for stoichiometry
Apply the molar mass in grams-to-moles conversions, percent composition problems, or reagent preparation steps.
Formula
M = \u2061\sum_i n_i M_i
M is the molecular weight, n_i is the number of atoms of element i, and M_i is the standard atomic mass of element i.
Example
For Ca(NO₃)₂: Ca (40.078) + 2 × [N (14.007) + 3 × O (15.999)] = 164.088 g/mol.
Full Description
Molecular weight (or molar mass) is the sum of atomic masses for all atoms in a chemical species. Accurate values are essential for stoichiometry, preparing standard solutions, and interpreting spectroscopy data.
This calculator leverages a full periodic table dataset to parse complex formulas, including nested parentheses, hydration states, and leading stoichiometric coefficients. It returns both the total molar mass and a detailed element-by-element breakdown.
The error reporting helps students and professionals alike spot syntax mistakes quickly, making the tool suitable for teaching, lab preparation, and rapid desk calculations.
Frequently Asked Questions
Can the calculator handle hydrates?
Yes. Use a dot (·) or period to separate hydrate parts, e.g., CuSO4·5H2O. Leading numbers multiply the following group correctly.
Does it support isotopic masses?
The calculator uses standard atomic weights. For isotopic calculations, replace the atomic masses on a per-element basis manually.
What about radicals or charges?
Charges do not affect molar mass directly. Enter only the elemental composition (e.g., SO4 for sulfate).
Why do I see parsing errors?
Error messages point to unbalanced parentheses, invalid symbols, or misplaced numbers. Correct the syntax and try again.
Can I copy the breakdown to reports?
Yes. Highlight the table and copy it into spreadsheets or lab notebooks for documentation.