Molar Mass Calculator
How to Use?
- 1
Select what to calculate
Choose moles, mass, or molar mass from the dropdown.
- 2
Enter the two known quantities
Use the unit dropdowns to choose g, mg, or kg – the calculator converts automatically.
- 3
Read your result
The result appears with its appropriate unit.
Worked Examples
Calculate moles from mass and molar mass
Given:inputs
Solve for:Moles n = m / M
Mass (m):5.0
Molar Mass M (g/mol):18.02
Result:calculated
Result:0.2775 mol
Calculate mass from moles and molar mass
Given:inputs
Solve for:Mass m = n × M
Moles n (mol):0.5
Molar Mass M (g/mol):58.44
Result:calculated
Result:29.22 g
Calculate molar mass from mass and moles
Given:inputs
Solve for:Molar mass M = m / n
Mass (m):100.0
Moles n (mol):2.5
Result:calculated
Result:40 g/mol
FAQs
1.What is the difference between molar mass and molecular weight?
+Molar mass is numerically equal to molecular weight but expressed in grams per mole. Molecular weight is a dimensionless quantity representing the sum of atomic masses. For practical chemistry, they are used interchangeably.
2.Can I calculate the molar mass of a compound without entering a formula?
+Yes – this calculator only needs numeric values. For molar mass of a compound, you would typically look it up or compute it from the periodic table, then enter the number.
3.Why are the results rounded differently for moles and mass?
+Moles often need higher precision (6 decimals) because they are used in stoichiometric calculations, while mass (4 decimals) is usually sufficient for lab measurements.