Enter a chemical formula to calculate molar mass, total atom count and each element's mass contribution.
Chemistry & lab
Parse elements, subscripts, parentheses and hydrate notation, then inspect atomic counts and mass composition.
Your entries stay in this browser and are used only for this calculation.
Molar mass
Molar mass and element-by-element composition will appear here.
Methodology
The parser identifies element symbols, integer subscripts, nested parenthesized groups and hydrate segments. Each atom count is multiplied by its atomic weight; those contributions are summed for molar mass and divided by the total to produce mass percentages.
Worked example
Ca(OH)₂ contains one Ca, two O and two H atoms. Using 40.078, 15.999 and 1.008 g/mol, its molar mass is 40.078 + 31.998 + 2.016 = 74.092 g/mol.
Formula entry
Write element symbols exactly: the first letter is uppercase and a second letter is lowercase. Parentheses repeat a whole ion or group, while a hydrate coefficient repeats the segment after the dot.
Academic reference
Related chemistry tools
Common questions
Count each element in the formula, multiply its count by its standard atomic weight, and add every element's contribution.
Yes. Formulas such as Ca(OH)2 and Al2(SO4)3 are parsed with the multiplier applied to the complete parenthesized group.
Yes. Use a middle dot or period, for example CuSO4·5H2O. The leading coefficient multiplies the entire water segment.
Molar mass has units of g/mol. Relative molecular mass is dimensionless, though their numerical values are typically the same for a stated formula.
Standard atomic weights can be expressed as intervals or rounded conventions. This calculator uses commonly published representative values.
Yes. Element symbols begin with an uppercase letter and may include one lowercase letter; CO and Co represent different compositions.
The calculator parses neutral formula notation, parentheses and dot hydrates. It does not infer a formula from a chemical name, balance reactions or distinguish isotopic enrichment. Confirm the exact compound and hydrate form on the reagent label before using a calculated mass in the laboratory.