Molar Mass Calculator
Work out the molar mass of a simple formula.
Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.
Molar Mass Calculator
How to use this tool
- Enter your details in the fields above.
- Press Generate to see the result.
- Use Load sample to try the worked example, or Clear to start again.
Worked example
For H2O, the mass is 2 x 1.008 (hydrogen) + 15.999 (oxygen) = 18.015 g/mol. For CO2 it is 12.011 + 2 x 15.999 = 44.009 g/mol.
What this tool does not do / Limits
Coverage is a common-element subset: H, C, N, O, Na, Mg, P, S, Cl, K, Ca, Fe, Zn, Cu, Al, Si, Br, I, He, Li, B, F, Ar, Mn, Co and Ni. Formulas with brackets, charges or elements outside this list are not supported.
Frequently asked questions
Which elements are covered?
A common subset of 25 elements, listed in the limits above. Anything outside it returns a message instead of a wrong number.
Does it handle brackets like Ca(OH)2?
No. Brackets and groups are not supported; only plain element symbols followed by counts.
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