Grams to Moles Calculator
Convert grams to moles and moles to grams with n = m/M. Enter the mass and molar mass, or solve for any of the three quantities.
n = mM
How to use this calculator
- Choose the quantity you want under “Solve for”.
- Type the known values and pick their units: any combination works.
- The result updates as you type. Open “Show the steps” to see the substitution.
The amount of substance n, in moles, links the mass you weigh on a balance to the number of particles. One mole contains 6.02214076 × 10²³ particles (the Avogadro constant).
Divide the mass by the molar mass to get moles, or multiply moles by the molar mass to get grams. If you do not know the molar mass, compute it first with the molar mass calculator.
Formula
n = mM
| Symbol | Quantity | Units |
|---|---|---|
| m | Mass | kg, g, mg, µg, t, lb, oz, st, US ton, ct, Da |
| M | Molar mass | g/mol, kg/mol |
| n | Amount of substance | mol, mmol, µmol, nmol, kmol |
Worked example
Given: m = 90.078 g · M = 18.015 g/mol
n = mM
Result: n = 5.00017 mol
Frequently asked questions
How do I convert grams to moles?
Divide the mass in grams by the molar mass in g/mol. For example, 90.08 g of water ÷ 18.015 g/mol = 5.000 mol.
How many particles are in a mole?
Exactly 6.02214076 × 10²³, the Avogadro constant fixed in the 2019 redefinition of the SI.