Molar Mass Calculator — Molecular Weight from Formula
Molar mass / molecular weight from a chemical formula (parentheses + hydrates) with a per-element breakdown. Client-side.
| Element | Count | Mass | Subtotal |
|---|---|---|---|
How to use
- 1 Type a chemical formula — use parentheses and · for hydrates (e.g. CuSO4·5H2O).
- 2 The molar mass in g/mol is shown instantly.
- 3 A breakdown shows each element’s contribution.
Why use this tool
- Parses parentheses and hydrates, not just simple formulas.
- Per-element breakdown so you can check the work.
- Uses standard atomic weights for all 118 elements. Runs in your browser.
Frequently asked questions
What is molar mass?
The mass of one mole of a substance, in grams per mole (g/mol). It equals the sum of the atomic masses of every atom in the formula.
How do I enter a hydrate?
Use a middle dot or a period before the water part, e.g. CuSO4·5H2O or CuSO4.5H2O.
Does it handle parentheses?
Yes — nested groups like (NH4)2SO4 and Ca(OH)2 are parsed correctly.
Where do the atomic masses come from?
Standard atomic weights; for radioactive elements without a stable isotope, the mass number of the most stable isotope is used.
What is Molar Mass Calculator?
A molar mass calculator computes the mass of one mole of a compound in grams per mole by summing the standard atomic weights of every atom in its chemical formula, including groups in parentheses and hydrates.
Features
Formula parser
Handles nested parentheses and hydrate dot notation (e.g. CuSO₄·5H₂O).
Standard atomic weights
Sums per-element contributions using IUPAC standard atomic weights.
Free & private
Runs on your device — nothing is uploaded.
Example
Input
H2OOutput
18.015 g/mol (2 × 1.008 + 15.999)Common use cases
-
1
Stoichiometry
Convert between grams and moles for a reactant or product.
-
2
Prepare solutions
Compute how many grams give a target number of moles.
-
3
Chemistry study
Check molar-mass calculations for homework and labs.
Zerethon's molar mass calculator parses a chemical formula — including parentheses and hydrates — and computes its molar mass from standard atomic weights, in your browser. Everything runs client-side — nothing is uploaded.
- Category
- Science
- Pricing
- Free
- Privacy
- Browser-based
- Signup
- Not required
References
- CIAAW — Atomic weights of the elements — IUPAC CIAAW
- Molar mass — Wikipedia
Privacy
Your data never leaves your browser unless explicitly stated. Molar Mass Calculator runs entirely client-side — no server upload, no logging, no tracking of your input.
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