Moles Calculator
The Mole Is Chemistry's Unit of Counting
Atoms and molecules are far too small and numerous to count individually, so chemistry counts them in bundles of roughly 6.022 × 1023 at a time — a mole. Converting between a mass you can weigh on a balance and a mole count you can use in a reaction equation is one of the most frequent calculations in any lab, and it depends entirely on knowing the substance's molar mass.
The Formula
Rearranged, this also gives mass from a known mole count: Mass = Moles × Molar Mass. This calculator accepts either a molar mass you already know, or a chemical formula it can parse and weigh for you automatically.
Where This Calculation Matters
- Weighing out reagents — a synthesis procedure specifying "0.5 mol of NaOH" needs converting to grams before anything gets measured on a balance.
- Stoichiometric calculations — every reactant-to-product conversion in a balanced equation runs through moles, not mass, so this conversion is a required first step.
- Preparing solutions — molarity calculations need a mole count derived from a measured mass of solute.
- Verifying a synthesis yield — comparing moles produced to moles of limiting reactant reveals percent yield.
Moles from 10 Grams of Common Compounds
| Compound | Molar Mass (g/mol) | Moles in 10 g |
|---|---|---|
| Water (H2O) | 18.015 | 0.5551 mol |
| Sodium chloride (NaCl) | 58.440 | 0.1711 mol |
| Glucose (C6H12O6) | 180.156 | 0.0555 mol |
| Sodium hydroxide (NaOH) | 39.997 | 0.2500 mol |
Values computed by dividing 10 g by each compound's molar mass (from the molar mass calculator's atomic weight table) and rounding to four decimal places.
How to Use This Calculator
- Enter the Mass (g) of the sample.
- Provide either the Molar Mass (g/mol) directly, or switch to entering a Chemical Formula (e.g. H2O) and let the calculator determine the molar mass itself.
- Select Calculate to get the number of moles.
Related Calculations
Don't know the molar mass off-hand? The Molar Mass Calculator parses any formula and computes it for you. Once you have a mole count, convert it into a solution concentration with the Molarity Calculator.