Molar Mass Calculator
Enter any formula — H₂O, Ca(OH)₂, C₆H₁₂O₆ — and get the molar mass in g/mol with a full element-by-element breakdown and mass percentages.
Open the calculator →Grams ⇄ Moles Converter
Convert between mass and moles for any substance, with Avogadro particle counts — the hub of every stoichiometry problem.
Open the calculator →pH Calculator
Convert between pH, pOH, [H₃O⁺] and [OH⁻] — with automatic acidic / neutral / basic classification.
Open the calculator →Ideal Gas Law (PV = nRT)
Solve for pressure, volume, moles or temperature with automatic unit conversion — atm, kPa, mmHg, L, mL, K, °C.
Open the calculator →Understand the chemistry behind the numbers
Molar mass is the mass of one mole of a substance, in g/mol — the sum of the atomic masses of every atom in the formula. Water (H₂O) contains 2 hydrogen atoms (1.008 u each) and 1 oxygen atom (16.00 u), so M(H₂O) = 2 × 1.008 + 16.00 = 18.02 g/mol. It is the bridge between the atomic scale and the lab scale: mass ÷ molar mass = moles, and one mole always contains 6.022 × 10²³ particles. Study it in the The Mole & Stoichiometry lesson.
pH measures how acidic or basic a solution is: pH = −log₁₀[H₃O⁺]. Each step of the scale is a tenfold change in acidity — lemon juice (pH 2) is 100,000 times more acidic than blood (pH 7.4). Pure water sits at 7 because [H₃O⁺] and [OH⁻] are equal. Study it in the Acids, Bases & pH lesson.
The ideal gas law, PV = nRT, links the pressure, volume, amount and temperature of a gas — and contains Boyle's, Charles's and Avogadro's laws as special cases. At 0 °C and 1 atm, one mole of any ideal gas occupies about 22.4 L. Study it in the States of Matter & Gas Laws lesson.
Take it with you: download the one-page formula cheat sheet (PDF) — print it and keep it on your desk.
Start with the The Mole & Stoichiometry lesson →