⚖️ Gram Equivalent Weight Calculator
Find the equivalent weight of an acid, base, or salt from its molecular weight and valence (n-factor), and optionally its normality in solution.
What gram equivalent weight is
Gram equivalent weight is the mass of a substance that supplies or reacts with one mole of a specified unit of chemical activity, such as one mole of replaceable hydrogen ions for an acid, one mole of hydroxide ions for a base, or one mole of electrons in a redox reaction.
The formula used
Equivalent weight = molecular weight ÷ n-factor. The n-factor depends on the substance’s role: for an acid it is the number of ionizable H+ per molecule, for a base it is the number of OH- (or H+ it can accept), for a salt it is the total positive (or negative) charge per formula unit, and for redox reactions it is the number of electrons transferred per molecule or ion. If you also enter a sample mass and solution volume, the calculator finds the gram equivalents present and the resulting normality (equivalents per liter).
- Sulfuric acid (H2SO4, MW 98.08) has n = 2, giving an equivalent weight of 49.04 g/eq.
- Normality = gram equivalents ÷ volume of solution in liters.
This tool is intended for general chemistry education and laboratory calculation purposes.