# Normality Calculator

URL: https://speedycalculator.com/calculators/chemistry/normality/
Last updated: 2026-10-30

> The normality calculator finds the concentration of a solution in equivalents per litre (N) from the mass of solute and its equivalent weight, from the mass, molar mass and number of equivalents per mole, or from molarity – with common acids, bases and oxidising agents built in.

## Inputs

- Calculate from
- Substance
- Molar mass (g/mol, kg/mol, Da (u), kDa)
- Equivalents per mole (n-factor) — Protons donated (acids), hydroxide ions accepted/donated (bases) or electrons transferred per formula unit (redox).
- Equivalent weight of solute (g/eq, mg/meq)
- Mass of solute (g, mg, µg, kg, oz, lb)
- Volume of solution (L, mL, µL, m³, dm³, cm³, US gal, fl oz (US))
- Molarity (mol/L (M), mmol/L (mM), µmol/L (µM), nmol/L (nM), mol/m³)

## Results

- Molar mass
- Equivalents per mole
- Equivalent weight
- Normality
- Equivalents of solute
- Molarity
- Mass of solute per litre
- Volume of a 1 N reagent that reacts with 1 L of this solution

## Formula

```
N = m ÷ (E × V) · E = M ÷ n_eq · N = c × n_eq
Number of equivalents = m ÷ E = n × n_eq
```

## Explanation

Normality expresses concentration in gram equivalents per litre of solution (eq/L, written N). An equivalent is the amount of a substance that supplies or reacts with one mole of reactive units: one mole of H⁺ in an acid–base reaction, one mole of OH⁻, or one mole of electrons in a redox reaction. So 1 M sulfuric acid, which can give up two protons, is 2 N, while 1 M hydrochloric acid is 1 N.

The advantage of normality is that equivalents always react one-to-one. At the end point of a titration, N₁V₁ = N₂V₂ regardless of how many protons or electrons each molecule carries. That is why normality is still common in water treatment (alkalinity and hardness in meq/L), clinical chemistry (electrolytes in mEq/L) and classical titrimetric analysis.

The catch is that the number of equivalents per mole depends on the reaction: phosphoric acid is 1, 2 or 3 N per mole depending on how far it is neutralised, and potassium permanganate supplies 5 electrons in acid but only 3 in neutral solution. IUPAC therefore discourages normality in favour of molarity, but it remains widely used. Choose a substance below or enter your own values.

### How to use the Normality Calculator

- **Calculate from**
- **Substance**
- **Molar mass**
- **Equivalents per mole (n-factor)** — Protons donated (acids), hydroxide ions accepted/donated (bases) or electrons transferred per formula unit (redox).
- **Equivalent weight of solute**
- **Mass of solute**
- **Volume of solution**
- **Molarity**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Choose your method. With an equivalent weight, normality is mass ÷ (equivalent weight × volume). With a molar mass, the equivalent weight is first found as molar mass ÷ equivalents per mole. From molarity, multiply by the equivalents per mole.

### Worked example

4.9 g of sulfuric acid (M = 98.072 g/mol, 2 acidic protons) is diluted to 500 mL. The equivalent weight is 98.072 ÷ 2 = 49.036 g/eq, so the solution contains 4.9 ÷ 49.036 = 0.09993 eq. Normality = 0.09993 eq ÷ 0.5 L = 0.1999 N, while the molarity is 4.9 ÷ 98.072 ÷ 0.5 = 0.0999 M – exactly half the normality.

### Equivalents per mole of common reagents

ReagentReactionEquivalents per moleEquivalent weight (g/eq)HClacid–base136.458H₂SO₄acid–base249.036H₃PO₄full neutralisation332.665NaOHacid–base139.997Ca(OH)₂acid–base237.046Na₂CO₃titrated to CO₂252.994KMnO₄redox, acidic (→ Mn²⁺)531.606K₂Cr₂O₇redox, acidic (→ Cr³⁺)649.030

### Tips

- Always start from a balanced equation – coefficients give the mole ratio.
- Convert everything to moles first, then use the ratio, then convert back.
- Every field has its own unit menu – g, mg, mol, mmol, L and mL all work.
- Everything is calculated in your browser.

### Common mistakes to avoid

- Using mass ratios instead of mole ratios.
- Forgetting water of crystallisation in the molar mass of hydrates.
- Confusing molarity (per litre of solution) with molality (per kilogram of solvent).

### Inputs explained

FieldWhat to enterCalculate fromChoose one: Mass, equivalent weight and volume, Mass, substance (molar mass and equivalents) and volume, Molarity and equivalents per moleSubstanceChoose one: Hydrochloric acid HCl (1 H⁺), Nitric acid HNO₃ (1 H⁺), Sulfuric acid H₂SO₄ (2 H⁺), Phosphoric acid H₃PO₄ (3 H⁺, full neutralisation) …Molar massUnits: g/mol, kg/mol, Da (u), kDaEquivalents per mole (n-factor)A number. Protons donated (acids), hydroxide ions accepted/donated (bases) or electrons transferred per formula unit (redox).Equivalent weight of soluteUnits: g/eq, mg/meqMass of soluteUnits: g, mg, µg, kg, oz, lbVolume of solutionUnits: L, mL, µL, m³, dm³, cm³ …MolarityUnits: mol/L (M), mmol/L (mM), µmol/L (µM), nmol/L (nM), mol/m³

### What each result means

- **Equivalents of solute** = [Mass of solute]÷[Equivalent weight]
- **Volume of a 1 N reagent that reacts with 1 L of this solution** = [Normality]×1000

## Worked example

Inputs — Calculate from: Mass, substance (molar mass and equivalents) and volume; Substance: Sulfuric acid H₂SO₄ (2 H⁺); Mass of solute: 4.9 g; Volume of solution: 0.5 L.

Results — Molar mass = 98.072 g/mol; Equivalents per mole = 2 eq/mol; Equivalent weight = 49.036 g/eq; **Normality = 0.199853 eq/L (N)**; Equivalents of solute = 0.099927 eq; Molarity = 0.099927 mol/L (M); Mass of solute per litre = 9.8 g/L; Volume of a 1 N reagent that reacts with 1 L of this solution = 199.85 mL.

## Key terms

- **Normality (N)**: Gram equivalents of solute per litre of solution.
- **Equivalent**: Amount of substance that reacts with or supplies one mole of H⁺, OH⁻ or electrons.
- **Equivalent weight**: Molar mass divided by the number of equivalents per mole, g/eq.
- **n-factor**: Number of equivalents per mole of a substance in a specific reaction.

## FAQ

**What is normality in chemistry?**
Normality is the number of gram equivalents of solute per litre of solution (eq/L, N). It equals molarity × the number of reactive units (H⁺, OH⁻ or electrons) per formula unit.

**What is the normality of 1 M H₂SO₄?**
2 N, because each molecule can donate two protons. 1 M HCl is 1 N and 1 M H₃PO₄ is up to 3 N.

**How do I convert normality to molarity?**
Divide by the equivalents per mole: M = N ÷ n. 0.5 N H₂SO₄ is 0.25 M.

**What is an equivalent weight?**
The mass that supplies one equivalent: molar mass ÷ equivalents per mole. For H₂SO₄ it is 98.072 ÷ 2 = 49.036 g/eq; for Na₂CO₃ titrated to CO₂ it is 105.988 ÷ 2 = 52.994 g/eq.

**What is the normality of KMnO₄?**
In acidic solution permanganate takes 5 electrons (MnO₄⁻ → Mn²⁺), so 0.02 M KMnO₄ is 0.1 N. In neutral solution (→ MnO₂) it takes only 3.

**Why use normality in titrations?**
Equivalents react 1 : 1, so N₁V₁ = N₂V₂ at the end point – 25.0 mL of 0.1 N acid needs exactly 25.0 mL of 0.1 N base, whatever the acid or base.

**What is meq/L?**
Milliequivalents per litre, 1/1000 of eq/L. Blood sodium of 140 mEq/L is 0.140 N (and 140 mmol/L, because Na⁺ has one charge).

**What formula does the Normality Calculator use?**
N = m ÷ (E × V) · E = M ÷ n_eq · N = c × n_eq.


## Sources

- [IUPAC Compendium of Chemical Terminology (Gold Book)](https://goldbook.iupac.org/)
- [OpenStax – Chemistry 2e](https://openstax.org/details/books/chemistry-2e)
- [LibreTexts Chemistry](https://chem.libretexts.org/)