About this Molecular Weight
In chemistry, determining the molecular weight (or molar mass) of a compound is the first step in stoichiometry. This tool parses chemical formulas and sums the atomic weights of the constituent elements found in the periodic table.
Who this calculator is for
- Chemistry students converting between grams and moles.
- Lab users checking molar mass before preparing a solution or reaction setup.
- Anyone validating a straightforward empirical or molecular formula against common atomic weights.
When to use it
- Find molar mass before using a molarity or stoichiometry formula.
- Check whether a handwritten chemistry formula produces the expected compound mass.
- Convert a known mass of compound into moles for lab calculations.
How to use this calculator
- Enter a Chemical Formula (e.g., NaCl, H2SO4, C6H12O6).
- Ensure elements are capitalized correctly (e.g., 'Co' is Cobalt, 'CO' is Carbon Monoxide).
- The result shows the total Molar Mass in g/mol.
Key assumptions
- Formulas must use standard capitalization for element symbols.
- This parser supports common formulas without grouped parentheses.
- Only elements included in the built-in atomic-weight table can be evaluated.
Accuracy and testing
Review formula sources, default test cases, assumptions, unit handling, rounding rules, and changelog for this calculator.
How this calculator works
The calculator splits the string into elements and counts.
Example for H₂O:
* Hydrogen (H): 1.008 × 2 = 2.016
* Oxygen (O): 15.999 × 1 = 15.999
* Total = 18.015 g/mol.
Inputs explained
Chemical Formula
Standard chemical notation. Supports common elements. Use standard capitalization (e.g., Na, Cl).
Understanding your results
The result is the mass of one mole of the substance. This value allows you to convert between grams and moles.
Example scenarios
Water
H2O -> 18.015 g/mol.
Glucose
C6H12O6 -> 180.156 g/mol.
Salt
NaCl -> 58.443 g/mol.
Key Features
- Periodic Table Data
- Instant Parsing
- High Precision
Tips & Best Practices
- Case matters! 'CA' is Carbon + Gold? No, C + A (invalid). 'Ca' is Calcium.
- This calculator supports basic empirical formulas. It does not currently support parentheses grouping (like Ca(OH)2) - please expand to CaO2H2.
Glossary of Terms
- Mole
- A standard scientific unit for measuring large quantities of very small entities such as atoms.
- Atomic Weight
- The average mass of atoms of an element.