About this tool
The Normality & Equivalent Weight Calculator is a free, in-browser chemistry tool that works with normality (N), the concentration of reactive equivalents per litre. Choose a mode to convert between molarity and normality, or to find normality directly from a dissolved mass, using the solute's n-factor — the number of reactive equivalents per mole (for example 2 for H₂SO₄, 1 for NaOH).
The relationships are N = M × n-factor and M = N ⁄ n-factor, and the equivalent weight is Mr ⁄ n-factor, where Mr is the molar mass in g/mol. In the from-mass mode the normality is N = (mass ⁄ equivalent weight) ⁄ volume, with mass in grams and volume in litres, so it counts the number of gram-equivalents dissolved per litre of solution. Molarity is then recovered as N ⁄ n-factor.
All calculations run locally in your browser and nothing is uploaded. In molarity-normality mode leave either M or N blank and it is solved from the n-factor; entering a molar mass additionally reports the equivalent weight. Normality is convenient for titrations because equal volumes of solutions of equal normality react exactly.