Normality Calculator
Convert molarity to normality using the n-factor.
Reactive units per molecule
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How it works
Normality is a concentration unit used in acid-base and redox chemistry that counts reactive equivalents rather than whole molecules, and this calculator converts molarity to normality using the n-factor. You enter the molarity and the number of equivalents each molecule provides, and it returns the normality in equivalents per litre, written N. The n-factor is what distinguishes normality from molarity: for an acid it is the number of hydrogen ions the molecule can donate, so hydrochloric acid has an n-factor of one and sulfuric acid, which donates two protons, has an n-factor of two. For redox reactions it is the number of electrons transferred. This means a two-molar sulfuric acid solution is four normal, because each molecule supplies two reactive equivalents. Normality is especially convenient for titrations, where equal volumes of solutions with the same normality react exactly, simplifying calculations. Although molarity is more common in modern chemistry, normality remains widely used in analytical and industrial settings, water treatment, and clinical labs. To use it, identify the n-factor for your reaction, since the same substance can have different n-factors in different reactions. Enter the molarity and equivalents to find the normality.
normality = molarity × equivalents (n-factor)
Normality expresses concentration in equivalents of reactive species per litre, rather than moles per litre. It equals the molarity multiplied by the n-factor, the number of reactive units each molecule provides, such as the number of hydrogen ions an acid can donate or the electrons transferred in a redox reaction. So a solution's normality can be one, two, or more times its molarity depending on how many equivalents each molecule contributes.
Source:Chemistry (equivalent concentration)
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Worked example
How to use this calculator
- 1
Enter your values
Enter molarity and equivalents (n-factor).
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
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Frequently asked questions
What is normality?
Normality is a measure of concentration expressed in equivalents of a reactive species per litre of solution, abbreviated N. It equals molarity times the n-factor, the number of reactive units each molecule provides. Normality is used mainly in acid-base and redox chemistry, where the number of reactive equivalents, rather than whole molecules, determines how substances combine.
What is the n-factor?
The n-factor, or number of equivalents, is how many reactive units a molecule contributes in a given reaction. For acids it is the number of donatable hydrogen ions; for bases the number of hydroxide ions; and for redox reactions the number of electrons transferred. Sulfuric acid has an n-factor of two because it can donate two protons, so its normality is twice its molarity.
How is normality different from molarity?
Molarity counts moles of a substance per litre, while normality counts reactive equivalents per litre. They are equal only when the n-factor is one. When a molecule provides more than one reactive unit, its normality exceeds its molarity by that factor. Molarity is a property of the substance alone, but normality depends on the specific reaction being considered.
Why is normality useful in titrations?
In a titration, equal volumes of solutions with equal normality react completely, because normality already accounts for the reactive equivalents involved. This makes the calculation straightforward: normality times volume of one solution equals normality times volume of the other at the endpoint. It removes the need to track mole ratios separately, which is why analysts historically favoured normality for titration work.
Can the same substance have different normalities?
Yes, because the n-factor depends on the reaction, not just the substance. Sulfuric acid acting as a diprotic acid has an n-factor of two, but if only one proton reacts in a particular process, its effective n-factor is one. Always determine the n-factor from how the substance behaves in your specific reaction before calculating normality.