Avogadro Calculator
Calculate molar mass and number of particles from mass, moles, and Avogadro’s constant.
Inputs
mol⁻¹
Exact SI value: 6.02214076 × 10²³ mol⁻¹.
Unit changes preserve the original entered mass to avoid conversion drift.
× 10^
mol
n = a × 10^b mol. Exponent b should be an integer.
Results
Molecular weight (molar mass)
g/mol
Computed from M = m / n.
Number of particles
× 10^
Computed from N = n × NA.
Step-by-step derivation
Enter values, then press Calculate to see the algebra with your numbers inserted.
References
- SI definition of the mole: NA = 6.02214076 × 10²³ mol⁻¹.
- Core relations: N = n × NA, n = m / M, so M = m / n.
- Mass factors used: 1 µg = 1e-6 g, 1 mg = 1e-3 g, 1 dag = 10 g, 1 kg = 1000 g, 1 oz = 28.349523125 g, 1 lb = 453.59237 g.
Use this Avogadro’s Number Calculator to calculate molar mass and the number of particles from a sample’s mass and amount in moles.
Avogadro Calculator Formulas
Avogadro’s constant is:
NA = 6.02214076 × 1023 mol−1
To calculate molar mass:
M = m ÷ n
To calculate the number of particles:
N = n × NA
- M: molar mass in g/mol
- m: sample mass in grams
- n: amount of substance in moles
- N: number of particles
Example
Suppose a sample has a mass of 18.02 g and contains 1.00 mol.
Molar mass = 18.02 ÷ 1.00 = 18.02 g/mol
Particles = 1.00 × 6.02214076 × 1023
Particles = 6.02214076 × 1023
The sample therefore has a molar mass of 18.02 g/mol and contains approximately 6.022 × 1023 specified particles.
Important Notes
- The entered mass and moles must refer to the same substance sample.
- Mass is converted to grams before molar mass is calculated.
- “Particles” may mean atoms, molecules, ions, electrons, or formula units, depending on the substance.
- Enter the coefficient and exponent of the mole value carefully when using scientific notation.
- The calculator does not identify a substance, determine its chemical formula, or account for sample purity.