A normality calculator with the formula and n-factor
This normality calculator finds the normality of a solution from the grams of solute and the volume, tells you how many grams to weigh for a solution of a given normality, converts between molarity and normality with the n-factor, and solves the titration equation N₁V₁ = N₂V₂. Type any formula, including hydrates such as CuSO₄·5H₂O, and the molar mass is worked out from IUPAC atomic weights.
It is built for chemistry students and lab staff who still meet normality in titration methods, pharmacopoeia monographs and water-testing procedures in India, the US and elsewhere. Common acids, bases and redox reagents are preset with their usual n-factors. Everything runs in your browser.
How to use the normality calculator
- Pick a calculation: From mass, Grams to weigh, M ↔ N or N₁V₁ = N₂V₂.
- Choose a substance from the list, or type its formula, and check the n-factor for your reaction.
- Enter the mass and volume, the target normality and purity, or the concentration to convert.
- For titrations, fill three of N₁, V₁, N₂ and V₂ and leave the unknown empty.
- Read the normality, molarity, equivalent weight and grams per litre, and press Copy result.
Normality Calculator features
Molar mass from the formula
Brackets, hydrates and charges are parsed, using IUPAC 2021 standard atomic weights.
n-factor presets
Acids, bases, carbonate, permanganate (acid and neutral), dichromate, ferrous and thiosulfate salts.
Four calculations
Normality from mass, grams for a target N with purity, M ↔ N, and N₁V₁ = N₂V₂.
Equivalent weight
Molar mass ÷ n with milliequivalents and g/L shown for every result.
Clear about the reaction
The n-factor note for each preset says which reaction it assumes.
Normality formula
Normality is the number of gram-equivalents of solute per litre of solution: N = equivalents ÷ volume (L) = M × n. Equivalents = moles × n, and the equivalent weight is molar mass ÷ n. So N = (mass ÷ equivalent weight) ÷ volume in litres.
Worked example: 4.904 g of sulfuric acid (98.07 g/mol) dissolved and made up to 500 mL is 0.05000 mol in 0.500 L, i.e. 0.1000 M. Each H₂SO₄ gives two H⁺, so n = 2 and the solution is 0.2000 N. Its equivalent weight is 98.07 ÷ 2 = 49.04 g/eq.
To prepare 1 L of 0.1 N KMnO₄ for an acidic titration (MnO₄⁻ → Mn²⁺ takes 5 electrons), you need 0.1 ÷ 5 = 0.02 mol, or 0.02 × 158.03 = 3.161 g.
How to find the n-factor
| Type of substance | n-factor is | Examples |
|---|---|---|
| Acid | H⁺ ions given per formula unit in the reaction | HCl 1, H₂SO₄ 2, H₃PO₄ 1–3 |
| Base | OH⁻ ions given (or H⁺ accepted) | NaOH 1, Ca(OH)₂ 2, Na₂CO₃ 2 |
| Oxidising / reducing agent | Electrons gained or lost per formula unit | KMnO₄ 5 (acid) or 3 (neutral), K₂Cr₂O₇ 6, Fe²⁺ 1 |
| Salt (precipitation) | Total positive charge | NaCl 1, CaCl₂ 2, Al₂(SO₄)₃ 6 |
Things to watch
- Normality depends on the reaction, so the same bottle can be 0.1 M, 0.1 N or 0.3 N depending on use; always state the reaction.
- IUPAC no longer recommends the terms normal and equivalent; many current methods quote molarity instead.
- For liquids such as concentrated acids, weigh by mass or use density and assay to find the volume; use the dilution calculator for the next step.
- N₁V₁ = N₂V₂ holds at the equivalence point; volumes may be in any unit as long as both sides match.
Normality Calculator FAQ
What is the formula for normality?
N = equivalents of solute ÷ litres of solution, which equals molarity × n-factor. From a mass: N = grams ÷ (equivalent weight × litres).
How do I convert molarity to normality?
Multiply by the n-factor: 0.5 M H₃PO₄ fully neutralised (n = 3) is 1.5 N. To go back, divide normality by n.
How is normality used in chemistry titrations?
At the end point the equivalents of titrant equal those of the analyte, so N₁V₁ = N₂V₂. If 25 mL of 0.1 N acid needs 20 mL of base, the base is 0.125 N.
What is the normality of 98% sulfuric acid?
About 36.8 N: 98% H₂SO₄ has a density near 1.84 g/mL, so 1 L holds 1,803 g of acid, which is 18.4 mol or 36.8 equivalents.
Is normality the same as molarity?
Only when n = 1, as for HCl or NaOH. For H₂SO₄ in acid-base work the normality is twice the molarity.
Is this normality calculator online free to use?
Yes, it is free and runs entirely in your browser. Results are for study and lab planning — follow your laboratory’s method for standardisation.