What Is the Molar Mass Calculator?
Molar mass is the mass of exactly one mole (6.022 × 10²³ formula units) of a substance, in g/mol.
How Does the Molar Mass Calculator Work?
Look up the atomic mass of each element, multiply by the atom count in the formula, and sum all contributions.
Molar Mass Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Sum atomic masses of all atoms, using IUPAC 2021 standard atomic weights.
How to Use the Molar Mass Calculator
- Type the chemical formula using standard element symbols. Subscripts are plain numbers after the symbol.
Step-by-Step Example Calculation
Water (H₂O)
Input Values:
formula:H2O
Worked Steps: M(H₂O) = 2 × 1.008 + 15.999 = 18.015 g/mol.
Understanding Your Result
Each row in the table shows an element's contribution. The sum is the total molar mass.
Factors That Affect the Result
- Isotope selection matters — the calculator uses standard (average) atomic weights, not isotopic masses.
When Should You Use This Calculator?
- Stoichiometry, solution preparation (molarity), analytical chemistry, drug dosing.
Assumptions & Limitations
- Uses standard atomic weights (weighted average of natural isotopes). Not suitable for isotopically pure samples.
Frequently Asked Questions
Calculation Accuracy & Reference Note
IUPAC 2021 standard atomic weights, five significant figures.