Mole Calculator

Divide the mass in grams by the molar mass in grams per mole: moles = mass / molar mass. For the default 18 g of water at 18.015 g/mol that is 18 / 18.015, which is about 0.999167 mol.

The exact 2019 SI value, 6.02214076 x 10^23 particles per mole. The tool multiplies moles by this to get particles, and divides a particle count by it to get moles.

Enter the amount in the moles field and the particle count appears automatically, since particles = moles x Avogadro's number. Enter moles = 1 and you get 6.0221 x 10^23 particles.

You need enough to fix the amount in moles: either moles directly, or a particle count, or both a mass and a molar mass together. Mass alone or molar mass alone is not enough, and the tool will say so.

The tool can still link moles and particles, but with no molar mass it cannot produce a mass, so the Mass card reads 0. Add a molar mass whenever you want grams in the answer.

Mass, molar mass and moles are rounded to nine decimal places, so tiny floating-point tails do not show. The particle count is rounded to the nearest whole particle and then displayed in scientific notation with four decimals, for example 6.0221e23.

Yes. The particles field accepts forms like 6.022e23 or 1.2e24, as well as plain integers. The value is read as a normal number, so either style gives the same result.

Mass, molar mass, moles and particle counts are all physical amounts that cannot be below zero, so a negative entry is treated as an error. A molar mass must also be greater than zero because it divides into the mass.

No. You supply the molar mass yourself. If you need the molar mass of a compound first, use a molar mass calculator, then bring that number back here to convert grams and moles.