Molar mass is the mass of one mole (6.022 × 10^23 particles) of a substance, expressed in grams per mole (g/mol). It is numerically equal to the molecular weight expressed in atomic mass units (u or Da).

How are hydrates handled?

Hydrates are written with a dot separator, for example CuSO4.5H2O. The calculator treats each dot-separated segment as a separate formula fragment, multiplies it by the coefficient that follows the dot, and sums the results.

Are parentheses and brackets supported?

Yes. The parser handles nested round parentheses such as Ca(OH)2 and Al2(SO4)3. Square brackets and curly braces are also accepted as equivalent grouping symbols.

Which atomic masses are used?

Atomic masses are taken from the 2021 IUPAC standard atomic weights, rounded to four decimal places. All 118 elements from hydrogen (H) to oganesson (Og) are included.

Molecular Weight Calculator

Name: Molecular Weight Calculator
Availability: InStock
Author: Nham Vu

Enter any chemical formula — including parentheses, subscripts, and hydrates — to instantly get the molar mass and a full element breakdown.

Chemical Formula

Formula

Common Formulas

Results

Live calculation

Enter a chemical formula to see its molar mass.

Try H2O, Ca(OH)2, or CuSO4.5H2O.

Molar Mass

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g/mol

Element Breakdown

Symbol	Count	Atomic Mass	Total (g/mol)	%

Summary

Enter any chemical formula — including parentheses, subscripts, and hydrates — to instantly get the molar mass and a full element breakdown.

How it works

Type a chemical formula into the input field (e.g. H2O or Ca(OH)2).
The molar mass and element breakdown table update automatically as you type.
Press the Calculate button or press Enter to trigger an explicit calculation.
Click a quick-formula button such as C6H12O6 to pre-fill a common compound.
Read the element breakdown table to see each element's atom count, atomic mass, subtotal mass, and percentage contribution.

Use cases

Chemistry students verifying molar mass for stoichiometry homework.
Lab technicians preparing solutions that require an exact mass of a compound.
Researchers cross-checking molecular weights of synthesized compounds.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu