How to use this calculator
- Enter or choose solve for.
- Enter or choose stock concentration (C₁).
- Enter or choose stock volume (V₁).
- Enter or choose final concentration (C₂).
- Enter or choose final volume (V₂).
- The answer updates as you type. Use Copy result or Share to keep it.
Method
C₁ × V₁ = C₂ × V₂; diluent = V₂ − V₁; dilution factor = C₁ ÷ C₂ = V₂ ÷ V₁
- C₁, V₁
- concentration and volume of the stock used
- C₂, V₂
- concentration and total volume after dilution
Worked example
- V₁ = C₂ × V₂ ÷ C₁ = 0.1 × 250 ÷ 1 = 25 mL.
- Solvent to add = 250 − 25 = 225 mL; dilution factor = 1 ÷ 0.1 = 10.
To make 250 mL of 0.1 M from 1 M stock, take 25 mL of stock and make it up to 250 mL (about 225 mL of solvent).
What the result means
In the lab, measure V₁ of stock into a volumetric flask and fill to the V₂ mark rather than adding exactly V₂ − V₁, because volumes are not always additive.
Assumptions and limits
- The solute amount is conserved and the stock and final concentrations use the same unit.
- Mixing some liquids (for example ethanol and water) changes the total volume, so “diluent to add” is approximate.
Questions
What does “1 in 10” dilution mean?
One part stock in ten parts total, a dilution factor of 10: for example 25 mL made up to 250 mL.
Can I use percentages or mg/mL?
Yes, as long as C₁ and C₂ are in the same unit.