Mole ↔ Mass Converter
Convert between grams and moles for any substance.
Free chemistry formula cheat sheet (PDF)
One page with the formulas you use most — molar mass, grams ⇄ moles, pH and PV = nRT — each with a worked example. Leave your email and we'll send it over.
Worked examples
58.44 g of NaCl ÷ 58.44 g/mol = 1.000 mol. One mole of salt contains 6.022 × 10²³ formula units — the converter shows the particle count automatically.
36 g of water ÷ 18.02 g/mol = 2.00 mol, which is about 1.2 × 10²⁴ water molecules. Drinking "a mole of water" (18 g) is just a small glass — moles connect the invisible atomic world to kitchen-scale amounts.
Switch the mode to Moles → Grams: 0.250 mol × 44.01 g/mol = 11.00 g. This is the direction you use when a balanced equation gives you moles but the lab balance reads grams.
How it works
The conversion uses one formula: n = m / M — moles equal mass divided by molar mass. To go the other way, multiply: m = n × M. The molar mass comes straight from the periodic table, summed over the formula (the Molar Mass Calculator finds it for you).
Moles are the hub of stoichiometry: balanced equations speak in moles, balances speak in grams, and Avogadro's number (6.022 × 10²³ mol⁻¹) speaks in particles — so almost every calculation in chemistry passes through a mole conversion at some point.
Take it with you: download the one-page formula cheat sheet (PDF) — print it and keep it on your desk.
Next steps: find any molar mass with the Molar Mass Calculator, then practice the full workflow in the The Mole & Stoichiometry lesson and the practice quiz.