Using the Molecular Weight Calculator
Element symbols are case sensitive: use the conventional capital letter followed by a lowercase letter where applicable. Parentheses multiply the whole enclosed group by the following subscript. The supported element list and syntax limits are described in the method below.
Worked example
Use the example inputs below to reproduce this result. These are the form's starting values, not recommended targets. Changing your inputs updates your result above; this worked example stays fixed for comparison. Results are rounded for display.
Example inputs
- Chemical formula
- Ca(OH)2
Example result
- Molar mass (g/mol)
- 74.092
Method and assumptions
Adds standard atomic weights with integer subscripts and nested parentheses. Supports common elements H–Ca plus Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, Ag, I, Ba, Pt, Au, Hg and Pb. Isotopes, hydrates and ionic charges are not supported.
Check the chemical identity and units
Chemical calculations require the formula and amount to describe the same substance. A different chemical form can have a different molar mass even when the common product name sounds similar. Keep grams, moles and liters distinct, and use the final quantity specified by the equation. This page performs arithmetic rather than validating a laboratory procedure.
Common question
Can I enter hydrates or charged ions directly?
This version does not support hydrate dots, ionic charges or isotope notation. It accepts the documented element symbols, integer subscripts and parentheses. Use a tool supporting the required notation when those distinctions matter to the calculation.
Guide updated .