Grams to Moles (g to mol

Converting sample mass in grams to chemical moles is the foundation of chemical stoichiometry, relating laboratory mass to Avogadro's particle count (6.022 × 10^23).

To use the Grams to Moles (g to mol) Chemistry Calculator, enter your Mass of Sample, Molar Mass of Compound (MW). The calculator instantly computes Amount in Moles (n), Total Molecules / Formula Units and more. Results update in real time as you change any input — no submit button needed.

How to Use This Calculator

Enter your Mass of Sample (e.g. 50.0 in grams (g)) and Molar Mass of Compound (MW) (e.g. 18.015 in g/mol (H₂O)). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Moles n = Mass (grams) ÷ Molar Mass (g/mol)

Millimoles (mmol) = Moles × 1,000

Total Molecules = Moles × 6.02214 × 10^23 molecules/mol

Worked Example

50.0 grams of Water H₂O:

Moles n = 50.0 / 18.015 = 2.7755 moles (2,775.47 mmol).

Total Molecules = 2.7755 × 6.02214 × 10^23 = 1.6714 × 10^24 H₂O molecules.

Understanding Your Result

Unit conversion precision: round to the same number of significant figures as your original measurement. Converting 6 feet to meters gives 1.8288 m — but if your measurement was approximate (±1 inch), expressing more than 2 decimal places is false precision. For international trade and technical specifications, SI units (meters, kilograms, liters) are the standard. US customary units (feet, pounds, gallons) differ from Imperial UK units: 1 US gallon = 3.785 L vs. 1 UK gallon = 4.546 L.