Ohm’s Law Calculator
V, I, R and power.
Open →
Science
Molar Mass Calculator
Enter a chemical formula to get its molar mass in g/mol.
Molar mass
—
g/mol.
| Formula | — |
|---|---|
| Grams per mole | — |
| — | |
| — |
Show our math
Enter your figures above to see the step-by-step working.
Everything computed client-sideEverything computed client-side — nothing leaves this page
How the Molar Mass Calculator Works
The molar mass of a compound is the sum of the atomic weights of all its atoms, in grams per mole. This calculator reads a chemical formula — including parentheses and subscripts like Ca(OH)₂ — looks up each element’s standard atomic weight, multiplies by how many of each atom there are, and adds them up.
Water, H₂O, is two hydrogens (2 × 1.008) plus one oxygen (15.999), giving 18.015 g/mol. Molar mass is the bridge between grams and moles, essential for stoichiometry.
molar mass = Σ (atomic weight × atom count)
Frequently Asked Questions
How do you calculate molar mass?
Add up the atomic weight of every atom in the formula. For H₂O: 2×1.008 + 15.999 = 18.015 g/mol.
What formats does it accept?
Standard chemical formulas with element symbols, subscripts and parentheses — H2O, C6H12O6, Ca(OH)2, and so on.
What is a mole?
The amount of a substance containing about 6.022×10²³ particles. One mole of a compound weighs its molar mass in grams.
More From The Desk
Same plain method, different figuresDensity Calculator
Mass ÷ volume.
Open →pH Calculator
pH and acidity.
Open →Force Calculator
F = mass × accel.
Open →Molarity
Same plain method, different figures.
Open →