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Chemistry

Molar Mass Calculator

Calculate molecular weight from a chemical formula, including parentheses and hydrates, with an element-by-element mass breakdown.

Explicit units and model assumptionsLocal calculations with worked examples
Chemistry workspace
Chemistry workspace

Check the units, concentration basis and assumptions before interpreting the result.

See the method

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Your chemistry result

Your result

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Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter chemical formula.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

Molar mass is the sum of each element’s atom count multiplied by its conventional atomic weight. Parentheses multiply a group; CuSO4·5H2O adds five water molecules.

A WORKED EXAMPLE

Using chemical formula = Ca(OH)2, the result is 74.092 g/mol. Change these example inputs to match your task; use the method above to check each step.

Understanding your result

Yes. Co is cobalt, while CO is carbon plus oxygen. Enter formulas with correct case; use a middle dot, such as CuSO4·5H2O, for a hydrate.

What to keep in mind

Uses rounded conventional weights for 81 listed elements, not exact isotope masses. Decimal subscripts, ionic charges and isotope annotations are not supported. Educational calculation only; use validated procedures for laboratory work.

Reference: PubChem periodic table — atomic masses

Common questions

Does capitalization matter?

Yes. Co is cobalt, while CO is carbon plus oxygen. Enter formulas with correct case; use a middle dot, such as CuSO4·5H2O, for a hydrate.

Are my inputs uploaded?

No. This calculation runs in your browser without an account or an external API.

Methodology maintained by ClarityKit. How these tools are built and checked.