Avogadro's Number Calculator
Convert between moles and number of particles.
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How it works
Avogadro's number is one of the defining constants of chemistry, and this calculator uses it to convert between moles and the raw number of particles in either direction. Enter a value and choose whether it is in moles or in particles, and the calculator returns the equivalent in the other unit. Avogadro's number, exactly 6.02214076 times ten to the twenty-third, is the count of particles, whether atoms, molecules, or ions, in exactly one mole of any substance. It is an almost unimaginably large number, which reflects how tiny individual particles are: a single teaspoon of water contains vastly more molecules than there are stars in the observable universe. The constant is what makes the mole useful, allowing chemists to count particles by weighing macroscopic amounts. Students meet it when converting between the lab-scale quantities they can measure and the particle-scale amounts that react, and it appears throughout stoichiometry, gas laws, and physical chemistry. This calculator is handy whenever you need the actual number of molecules in a sample or want to express a huge particle count as a convenient number of moles. Enter your value and select its unit to convert.
particles = moles × 6.022 × 10²³
Avogadro's number, about 6.022 times ten to the twenty-third, is the number of particles in one mole. To convert moles to particles, multiply by Avogadro's number; to convert particles back to moles, divide by it. This constant is the fixed bridge between the amount of substance measured in moles and the actual count of atoms, molecules, or ions, letting chemists move freely between the two scales.
Source:Chemistry (Avogadro constant)
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How to use this calculator
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Frequently asked questions
What is Avogadro's number?
Avogadro's number is 6.02214076 times ten to the twenty-third, the number of particles in exactly one mole of any substance. It can count atoms, molecules, ions, or any specified particles. As a defined constant since the 2019 redefinition of the SI units, it fixes the relationship between the mole and the number of elementary entities, underpinning all mole-based chemistry.
How do I convert moles to particles?
Multiply the number of moles by Avogadro's number, 6.022 times ten to the twenty-third. For example, 0.5 moles contains 0.5 times that constant, about 3.011 times ten to the twenty-third particles. Select the moles option in the calculator, enter your value, and it returns the particle count. To go the other way, divide the particle count by Avogadro's number.
Why is Avogadro's number so large?
The number is enormous because individual atoms and molecules are extraordinarily small. To gather a mole, an amount with a mass in grams equal to the molar mass and easy to weigh, you need an astronomically large count of these tiny particles. The scale of Avogadro's number reflects the vast gap between the microscopic world of particles and the macroscopic samples we handle.
Is Avogadro's number the same as the Avogadro constant?
They are closely related. Avogadro's number is the pure count, 6.02214076 times ten to the twenty-third, while the Avogadro constant is the same value carrying units of per mole. In everyday chemistry the terms are often used interchangeably, and the numerical value is identical. This calculator uses the value as the count of particles per mole.
What can I count with it?
Avogadro's number counts whatever elementary entities you specify: atoms in a mole of an element, molecules in a mole of a compound, ions in a mole of an ionic species, or even formula units. The key is that one mole always contains this same number of the chosen particles, so the conversion works identically regardless of what the particles are.