How to calculate molar mass
The molar mass of a compound is the mass of one mole of it, in grams. You find it by adding up the atomic mass of every atom in the chemical formula. This calculator parses the formula for you, including brackets like Ca(OH)2, and shows the contribution of each element.
How it works
Each element's atomic mass (from the periodic table) is multiplied by how many of that atom appear in the formula, and the results are added together. The answer is in grams per mole (g/mol).
Worked example
For H2SO4: hydrogen is 2 x 1.008, sulfur is 32.06, and oxygen is 4 x 16.00. Added together that is about 98.08 g/mol.
Frequently asked questions
How do I write the formula?
Use standard notation: element symbols with numbers for counts, like H2O, NaCl or Ca(OH)2. Capitalisation matters, so use Co for cobalt and CO for carbon monoxide.
Does it handle brackets?
Yes. Groups in brackets such as Ca(OH)2 or Al2(SO4)3 are expanded and counted correctly.
What is molar mass used for?
Converting between grams and moles, which is the starting point for almost every chemistry calculation, including molarity and reaction amounts.