Molecular Weight (Molar Mass) Calculator

Molecular Weight – Quick Cheat Sheet

Elements: Use correct symbols (case-sensitive): H, He, Li, Fe, etc.
Counts: Numbers follow symbols/groups (e.g., H², (OH)³).
Groups: Parentheses for sub-units: (NH4)2SO4.
Hydrates: Use · or . between parts: CuSO4·5H2O.
Spacing: Whitespace is ignored. Nested parentheses are supported.
Output: Shows total g/mol and per-element mass & percent composition.
Limits: Unknown symbols trigger an error; isotopes (e.g., ^13C) aren’t parsed here.

Notes & edge cases

Atomic weights are conventional IUPAC values; rounding is to 4–5 decimals.
For polymer repeats like (CH2)50, just place the repeat count after the group.
Charges (e.g., SO4^2−) don’t affect mass and are ignored; omit them.