Normality calculator explained
Normality counts reactive equivalents per liter, so it tells you how many protons, hydroxide ions, or electrons a solution can deliver in the reaction you care about. This calculator connects {solute} mass, {equivalentweight}, and {solution} volume so you can move between grams, molarity, and normality without re-deriving valence factors.
Use it when reporting titration standards, comparing oxidizers, or setting feed rates in water treatment systems that dose based on equivalents.
How the conversion works
Normality is defined as:
where is the solute mass, is the equivalent weight (molar mass divided by the number of reactive units), and is solution volume in liters. For acids and bases, . For redox systems, divide by the number of electrons exchanged per mole.
Units and conversions
| Quantity | Symbol | Units | Notes |
|---|---|---|---|
| Normality | eq/L | Equivalent to mol/L multiplied by the valence factor. | |
| Mass | g | Use dry mass of the solute. | |
| Equivalent weight | g/eq | . | |
| Volume | L | Convert mL to liters before dividing. |
Worked examples
- Preparing 0.100 N sulfuric acid
(HSO) = 98.08 g/mol, delivers two protons in acid-base reactions so . To make 1.00 L of 0.100 N solution:
Weigh 4.90 g, dissolve cautiously, and dilute to a liter mark.
- Stocking KMnO for redox titrations
In acidic media permanganate accepts five electrons, so . To prepare 250 mL of 0.0200 N solution:
The calculator also reports the corresponding molarity (0.00400 M) for reference.
Tips and pitfalls
- Always state the reaction context because depends on how the solute reacts.
- Use normality for titration reporting but switch to molarity for thermodynamic calculations so units remain SI-compliant.
- Re-standardize concentrated acids frequently; evaporation shifts and therefore .
- When uncertainty matters, propagate the valence factor as an exact integer and keep mass and volume measurements in consistent units.