Dilution calculator
Enter three of the four values and choose the one to solve for. The box for the quantity you solve for is ignored. Concentrations can be in any unit, as long as C1 and C2 use the same one, and the same goes for the volumes.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Choose the value to solve for.
- Enter the other three values and pick labels for the units.
- Read the answer, the volume of solvent to add and the dilution factor.
How it works
Solute amount is conserved, so C₁V₁ = C₂V₂. Solved forms are C₁ = C₂V₂ ÷ V₁, V₁ = C₂V₂ ÷ C₁, C₂ = C₁V₁ ÷ V₂ and V₂ = C₁V₁ ÷ C₂. The solvent to add is V₂ − V₁.
Worked example
To make 500 mL of 1 M from 12 M stock: V₁ = 1 × 500 ÷ 12 = 41.67 mL, so add 458.33 mL of solvent. The dilution factor is 12.
Tips
- Wear suitable protection and add concentrated acid to water, not the other way around.
- Because a dilution only lowers concentration, the tool rejects a final concentration above the stock.
Frequently asked questions
What is the dilution equation?
C1 × V1 = C2 × V2. The amount of solute does not change when you add solvent, so concentration times volume is the same before and after. It holds when the concentration is per unit volume, such as mol/L or mg/mL.
Do I need to use litres and moles?
No. Any concentration unit and any volume unit work, as long as both concentrations share a unit and both volumes share a unit. The unit selectors only label the results.
How do I make 500 mL of 1 M solution from 12 M stock?
Solve for V1 with C1 = 12, C2 = 1 and V2 = 500. V1 = 1 × 500 ÷ 12 = 41.67 mL of stock, brought up to 500 mL with water (458.33 mL added, if volumes were additive).
Are the volumes of stock and solvent additive?
For dilute aqueous solutions they are close to additive, but mixing some liquids changes the total volume. For accurate work, add the stock to a flask and fill to the final volume mark.