Chemistry

Grams to Moles Calculator (and Moles to Grams)

Enter a formula and a mass or amount to convert between grams and moles.

By TheCalcTools Updated Formula checked and tested

Your numbers

Your results

Result
Result
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Molar mass (g/mol)
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Number of molecules or formula units
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Millimoles
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Grams to Moles Calculator (and Moles to Grams) by TheCalcTools

How the Grams to Moles Calculator (and Moles to Grams) works

Moles = mass ÷ molar mass, and mass = moles × molar mass. The molar mass is worked out from the formula using IUPAC atomic weights.

Multiply moles by the Avogadro constant (6.02214076 × 10²³ per mole, exact since 2019) to get the number of particles.

The formula

n = m ÷ M; m = n × M; particles = n × 6.02214076 × 10²³

Worked example

Using the default values shown in the calculator:

Chemical formulaNaCl
ConvertGrams to moles
Mass (g)25
Amount (mol)0.5
  1. NaCl is 58.440 g/mol.
  2. 25 g ÷ 58.440 g/mol = 0.42779 mol.

Result:

Result0.42779 mol
Molar mass (g/mol)58.440
Number of molecules or formula units2.576e+23
Millimoles427.79

Frequently asked questions

How many moles are in 100 g of water?

Water is 18.015 g/mol, so 100 g is 5.551 mol.

Sources and further reading

Molar Mass Calculator (Molecular Weight from Formula)Type a chemical formula to get its molar mass and percent composition Moles CalculatorConvert grams to moles and molecules Molarity CalculatorFind molarity and moles from a mass of solute dissolved in a volume Limiting Reagent CalculatorEnter two reactants and the balanced equation coefficients to find which one runs out… Percent Composition Calculator (Mass Percent)Enter a formula and an element to get its mass percent and how much is in your sample

More in Chemistry · All calculators

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