Chemistry calculator
Mole Calculator
Move between sample mass, amount of substance, and molar mass.
Calculated moles
2 mol
How the mole calculator works
Select the unknown quantity and enter the other two. Mass is expressed in grams, amount in moles, and molar mass in grams per mole so units cancel consistently.
Molar mass must be positive when used as a divisor, and moles must be positive when solving for molar mass. A sample mass itself may validly be zero.
Worked example
A 36.03 g water sample with molar mass 18.015 g/mol contains 36.03÷18.015 = 2.000 mol. Reversing the calculation, 2.000 mol×18.015 g/mol returns 36.03 g.
Assumptions and practical limits
Convert kilograms to grams by multiplying by 1,000 and milligrams by dividing by 1,000 before entry.
Molar mass must come from the correct formula and appropriate atomic weights. This tool does not infer identity or account for sample purity.
Frequently asked questions
How do I convert milligrams?
Divide milligrams by 1,000 to enter grams.
Can mass be zero?
Yes, zero mass gives zero moles when molar mass is positive.
Does this count molecules?
No. Multiply moles by Avogadro’s constant if a particle count is needed.