Can I solve for different variables?

Yes! This calculator supports reverse solving. You can solve for: Mass, Moles, Molecular weight, Molecules.

Mole

Solve mole relationships quickly using core chemistry formulas.

Formula shown3 inputs definedUpdated Nov 2025By Automated Chemistry GeneratorFree, no sign-up

Quick Summary

Use this when you need:

Convert between grams, moles, and molecule counts in introductory problems
Estimate how much reagent to weigh out from a desired mole amount
Explain Avogadro's number by translating moles into molecule counts

You’ll need:Moles, Molecular weight, Molecules

You’ll get:Mass

How this is calculated

Formula:

mass (kg) = molecular weight × moles / 1000; molecules = moles × N_A

In plain language:

Mass equals the number of moles times molecular weight (converted to kilograms here), and multiplying moles by Avogadro's number N_A gives the number of individual molecules.

The formula is always visible so you can verify the math and explain your numbers to anyone who asks.

What these terms mean

Mass

Mass used in the calculation.

Moles

Moles used in the calculation.

Molecular weight

Molecular weight used in the calculation.

Molecules

Molecules used in the calculation.

When to use this calculator

Convert between grams, moles, and molecule counts in introductory problems
Estimate how much reagent to weigh out from a desired mole amount
Explain Avogadro's number by translating moles into molecule counts

Last updated: November 19, 2025

Mole calculator explained

The mole links the macroscopic world (grams) to the microscopic world (atoms and molecules). This calculator combines the basic relationships $m = nM$ and $N = n N_A$ so you can enter any pair of values—mass {mass}, molecular weight {molecularweight}, moles {mole}, or number of molecules {molecules}—and solve for the others instantly.

Use it when scaling stoichiometric calculations, translating reagent specs into grams, or teaching how Avogadro's number connects to laboratory measurements.

How the conversion works

Key relationships:

m = n M, \\qquad N = n N_A

where $m$ is mass, $n$ is moles, $M$ is molar mass, $N$ is number of particles, and $N_A = 6.02214076 \\times 10^{23}\\ \\text{mol}^{-1}$ is the Avogadro constant. The calculator optionally reports mass in kilograms depending on the unit system you choose.

Units and conversions

Quantity	Units	Notes
Mass $m$	g or kg	Choose the same unit you weigh in.
Moles $n$	mol	Derived from $m/M$ .
Molar mass $M$	g/mol	Sum atomic weights or pull from SDS.
Molecules $N$	count	$N = n N_A$ .

Worked examples

How many grams for 0.250 mol NaCl?
$M = 58.44\\ \\text{g}\\,\\text{mol}^{-1}$ , $n = 0.250\\ \\text{mol}$ .

m = 0.250 \\times 58.44 = 14.6\\ \\text{g}

The calculator also reports $N = 0.250 \\times 6.022 \\times 10^{23} = 1.51 \\times 10^{23}$ formula units.

Convert grams to molecules
A vial contains $3.00\\ \\text{g}$ of glucose (C $_6$ H $_{12}$ O $_6$ , $M = 180.16\\ \\text{g}\\,\\text{mol}^{-1}$ ).

n = \\frac{3.00}{180.16} = 1.67 \\times 10^{-2}\\ \\text{mol}

N = 1.67 \\times 10^{-2} \\times 6.022 \\times 10^{23} = 1.01 \\times 10^{22}\\ \\text{molecules}

Tips and pitfalls

Keep track of significant figures; Avogadro's constant is exact in the SI, but your mass measurements are not.
Always match the molar mass unit to the mass unit; using kg with g/mol produces errors.
For hydrates or salts with water of crystallization, include the water molecules in the molar mass.
When counting atoms instead of molecules, multiply $N$ by the number of atoms per formula unit.

References and further reading

Frequently Asked Questions

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Calculator info

Version:: v1.0.0
Last reviewed:: Nov 15, 2025
Sensitivity:: low
References:: 1

Last updated: November 19, 2025

Mole calculator explained

Use it when scaling stoichiometric calculations, translating reagent specs into grams, or teaching how Avogadro's number connects to laboratory measurements.

How the conversion works

Key relationships:

m = n M, \\qquad N = n N_A

Units and conversions

Quantity	Units	Notes
Mass $m$	g or kg	Choose the same unit you weigh in.
Moles $n$	mol	Derived from $m/M$ .
Molar mass $M$	g/mol	Sum atomic weights or pull from SDS.
Molecules $N$	count	$N = n N_A$ .

Worked examples

How many grams for 0.250 mol NaCl?
$M = 58.44\\ \\text{g}\\,\\text{mol}^{-1}$ , $n = 0.250\\ \\text{mol}$ .

m = 0.250 \\times 58.44 = 14.6\\ \\text{g}

The calculator also reports $N = 0.250 \\times 6.022 \\times 10^{23} = 1.51 \\times 10^{23}$ formula units.

Convert grams to molecules
A vial contains $3.00\\ \\text{g}$ of glucose (C $_6$ H $_{12}$ O $_6$ , $M = 180.16\\ \\text{g}\\,\\text{mol}^{-1}$ ).

n = \\frac{3.00}{180.16} = 1.67 \\times 10^{-2}\\ \\text{mol}

N = 1.67 \\times 10^{-2} \\times 6.022 \\times 10^{23} = 1.01 \\times 10^{22}\\ \\text{molecules}

Tips and pitfalls

Keep track of significant figures; Avogadro's constant is exact in the SI, but your mass measurements are not.
Always match the molar mass unit to the mass unit; using kg with g/mol produces errors.
For hydrates or salts with water of crystallization, include the water molecules in the molar mass.
When counting atoms instead of molecules, multiply $N$ by the number of atoms per formula unit.

Quick Summary

Calculator Tool

How this is calculated

What these terms mean

Mass

Moles

Molecular weight

Molecules

When to use this calculator

Mole calculator explained

How the conversion works

Units and conversions

Worked examples

Tips and pitfalls

References and further reading

Frequently Asked Questions

Related Calculators

Molarity

Reconstitution

Molar mass of gas

Radioactive decay

Mole fraction

pKa

Was this calculator helpful?

Found an error?

Calculator info

Mole calculator explained

How the conversion works

Units and conversions

Worked examples

Tips and pitfalls

References and further reading

Frequently Asked Questions

Related Calculators

Molarity

Reconstitution

Molar mass of gas

Radioactive decay

Mole fraction

pKa

Was this calculator helpful?

Found an error?

Calculator info