Mole Converter
Grams to moles to particles with Avogadro number.
What it does
Mole conversion walks the bridge between weighable grams and countable particles. Divide grams by molar mass for moles, then multiply by Avogadro number for molecules, with millimoles covering bench scale pipetting.
The tool above takes grams with molar mass. It returns moles with particle count and millimoles beside them.
The default 18.015 g of water at 18.015 g/mol is exactly 1 mol: 6.022e23 molecules, 1000 mmol. The same path turns 58.44 g of salt into 1 mol of formula units.
The Avogadro constant is exact at 6.02214076e23 per NIST CODATA with IUPAC amount of substance definitions behind it. Both treat particles as molecules, atoms, ions, or formula units by context.
How to use
- Enter the weighed grams.
- Enter the molar mass from the element math.
- Read moles first for reaction ratios.
- Read particles for the counting scale.
- Use millimoles for small bench batches.
Formula
- molar mass
- Grams per mole from atomic weights.
- 6.02214076e23
- Exact particles per mole.
- mmol
- Thousandths of a mole for small work.
Particle identity follows the substance: molecules for water, formula units for salts, atoms for elements. Purity scales the grams first when technical grade.
Worked example
Example: 18.015 g water
Grams 18.015, molar mass 18.015.
- Moles: 18.015 / 18.015 = 1 mol.
- Particles: 1 x 6.02214076e23 = 6.022e23.
- Millimoles: 1 x 1000 = 1000 mmol.
- Check: a liter of water holds about 55.5 mol.
- Tool shows 1 mol, 6.022e23, 1000 mmol.
Reference table
| Substance | Grams | Particles |
|---|---|---|
| Water | 18.015 g | 6.022e23 |
| Table salt | 58.44 g | 6.022e23 |
| Carbon-12 | 12 g | 6.022e23 |
| Glucose | 180.156 g | 6.022e23 |
Limits
- Pure substance assumed; mixtures need fractions.
- Identity (molecule vs atom) set by context.
- Display rounds particles to 4 digits.
- Reactions need balanced ratios beside it.
Common mistakes
- Dividing molar mass by grams instead.
- Using atomic number for molar mass.
- Reading mmol as micromoles (1000x off).
- Counting waters of hydration out.
- Rounding grams before dividing.
Try it yourself
Quick checks. Answers sit tucked under each question.
58.44 g NaCl at 58.44?
1 mol, 6.022e23 units, 1000 mmol.
9 g water at 18.015?
0.4996 mol, about half Avogadro.
Millimoles in 2.5 mol?
2.5 x 1000 = 2500 mmol.
Questions
How do you convert grams to moles?
Divide by molar mass: 18.015 g water is 1 mol.
What is Avogadro number?
6.02214076e23 particles per mole, exact by SI definition.
Moles to molecules?
Multiply by Avogadro: 2 mol holds 1.204e24.
What is a millimole?
A thousandth of a mole, handy for bench batches.
Atoms or molecules?
Context decides: water molecules, salt formula units, metal atoms.
Why such big numbers?
Atoms weigh almost nothing, so everyday grams hold 10^23 of them.