Molecular Weight Calculator
Calculate molecular weight from mass and moles
About this calculator
This molecular weight calculator determines the molecular weight of a substance using the fundamental relationship between mass, moles, and molecular weight (MW = mass/moles). It's an essential tool for chemistry students, researchers, and professionals who need to quickly convert between these key measurements. Understanding molecular weight is crucial for stoichiometric calculations, solution preparations, and chemical analysis in laboratory work.
How to use
Enter the mass of your substance in grams and the number of moles into the respective input fields. Click calculate to instantly determine the molecular weight in grams per mole (g/mol). The result shows how much one mole of your substance weighs.
Frequently asked questions
What units does this calculator use?
The calculator uses grams for mass, moles for amount of substance, and returns molecular weight in grams per mole (g/mol).
How do I find the number of moles if I don't know it?
You can calculate moles by dividing mass by molecular weight, or use Avogadro's number if you know the number of molecules.
What's the difference between molecular weight and molar mass?
Molecular weight and molar mass are numerically identical, but molecular weight is dimensionless while molar mass has units of g/mol.