Molecular Weight Calculator
Work out the molar mass of any chemical formula.
Adding up atomic masses
The molar mass of a compound is the sum of the atomic masses of all its atoms. Type the formula, using brackets for groups such as (OH)2, and the calculator adds everything and shows the share of each element.
Example
With the starting values shown (Chemical formula C6H12O6), Molar mass comes out as 180.156 g/mol. Other results include elements: 3; atoms in one molecule: 24.
Atomic masses use standard values rounded to a few decimals. The calculator covers the common elements up to uranium. Hydrates written with a dot, such as CuSO4·5H2O, are not supported, so add the water yourself.
Frequently asked questions
How do I write a formula with brackets?
Write it normally, for example Ca(OH)2 or Fe2(SO4)3. The number after the bracket multiplies the group.
Is it case sensitive?
Yes. Co is cobalt but CO is carbon and oxygen.
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