Normality calculator
N = n × M — concentration in equivalents per litre.
May be fractional (e.g. 0.5); only zero and negative values are rejected.
Supplying it adds the equivalent weight = MW ÷ n.
n-factor reference
Select a species to fill its conventional n-factor.
Fill every value except the one you are solving for — the equivalent weight appears too when a molar mass is supplied.
Formula and how to use it
Normality expresses the concentration of reactive equivalents rather than molecules: N = n × M, where M is molarity and n is the n-factor, the number of equivalents supplied per mole. For an acid, n is the number of ionisable protons; for a base, the number of hydroxide ions; for a redox reagent, the number of electrons transferred per formula unit.
Worked example: 0.1 M sulfuric acid is 0.2 N because H₂SO₄ supplies two protons per molecule (n = 2). A 0.02 M potassium permanganate solution is 0.1 N in acidic medium, where MnO₄⁻ gains five electrons on reduction to Mn²⁺ (n = 5), and 0.06 N in neutral medium (n = 3). The same molarity therefore has different normality in different reactions.
This calculator solves any one of N, n, or M from the other two and, when a molar mass is supplied, reports the equivalent weight = MW ÷ n. The n-factor table gives conventional values for common acids, bases, and salts; n may be fractional and any positive value is accepted, while zero is rejected.