Mole Calculator
Convert a mass or a number of particles into moles, with the equation shown.
What is Moles?
A mole is simply a count: 6.022 × 10²³ particles, chosen so that a mole of a substance weighs its molar mass in grams. Two completely different measurements therefore both convert into moles — a mass, if you know the molar mass, and a particle count, if you do not. This calculator accepts either.
How it works
For a mass the tool applies n = m ÷ M, and the molar mass can either be typed directly or derived from a formula. For a particle count it applies n = N ÷ Nₐ using Avogadro's number. Both routes are shown as the equation with your numbers in it, because the unit cancellation — grams over grams per mole leaving moles — is the part worth seeing.
- Enter what you know. Every field recalculates as you type — there is no submit button. Leave the quantity you want blank and the page solves for it.
- Read the answer and the working. The result appears above the fold; underneath it is the formula with your numbers substituted, so the arithmetic can be checked rather than trusted.
- Check the units and the size. Units are shown on every value and selectable per field, so a result in kJ, kPa or km/h is converted rather than assumed. Sanity-check the magnitude against a known landmark such as 1 g/cm³ for water.
Examples
A textbook problem with a known answer
Every tool here is checked against standard example problems — the molar mass of C6H12O6 is 180.16 g/mol, and free fall from 20 m takes about 2.02 s at g = 9.8 m/s².
A result you want to reason backwards from
Leave the quantity you already know blank instead: given the final answer, most tools recover the starting value — the mass needed for a target concentration, or the height a fall must have had.
Common mistakes
Forgetting that a formula is only as good as its subscripts
H2O and H2O2 are different compounds. The formula field shows its parse — element by element — so a mis-typed subscript is visible before it reaches the arithmetic.
Mixing units in the middle of a calculation
The most common source of a wrong answer is a value in grams next to a formula expecting kilograms, or Celsius next to a gas constant expecting kelvin. This category converts on the way in and labels what it used.
Frequently asked questions
What is a mole?
A mole is 6.02214076 × 10²³ particles — Avogadro's number. It is defined so that one mole of carbon-12 weighs exactly 12 grams, which is why the number is not a round one.
What is the difference between moles and molecules?
Molecules are what you can count; moles are how chemists count them in bulk. One mole of water contains 6.022 × 10²³ water molecules — the Molecules ↔ Moles converter does that multiplication.
Can I enter a particle count in scientific notation?
Yes, in the form 1.2044e24. A count that large is normally written that way, and typing the zeros out by hand is where the mistakes come from.