Grams to Moles Calculator
Enter a mass in grams and a molar mass (g/mol) — or pick a common substance — to calculate the number of moles instantly.
Conversion Inputs
Tip: select a substance above to auto-fill.
Enter a mass and molar mass, then click Calculate.
Result
mol
Step-by-step working
1.
Formula: moles = mass / molar mass
2.
3.
Quick reference — common molar masses
| Substance | Formula | g/mol |
|---|---|---|
| Water | H2O | 18.015 |
| Carbon dioxide | CO2 | 44.010 |
| Sodium chloride | NaCl | 58.440 |
| Glucose | C6H12O6 | 180.160 |
| Sulfuric acid | H2SO4 | 98.079 |
| Ammonia | NH3 | 17.031 |
| Ethanol | C2H5OH | 46.069 |
| Calcium carbonate | CaCO3 | 100.087 |
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Summary
Enter a mass in grams and a molar mass (g/mol) — or pick a common substance — to calculate the number of moles instantly.
How it works
- Enter the mass of your sample in grams.
- Either select a substance from the preset list to auto-fill its molar mass, or type the molar mass in g/mol manually.
- The calculator divides the mass by the molar mass to give moles.
- The formula and intermediate values are displayed below the result.
Use cases
- Determine the number of moles in a weighed sample before a chemical reaction.
- Cross-check reagent quantities when preparing solutions of a known molarity.
- Help students verify stoichiometry calculations from a chemistry textbook.
- Quickly convert bulk measurements in a lab to moles for yield calculations.
- Check mole quantities when scaling up or down a synthesis procedure.
Frequently Asked Questions
Last updated: 2026-06-18 ·
Reviewed by Nham Vu