Process Design
Dilution Calculator
The dilution equation C₁V₁ = C₂V₂ relates starting and final concentrations and volumes for a simple dilution. This calculator solves for any one of the four variables when the other three are provided. It also calculates the volume of solvent to add when applicable.
TypeInteractive calculator — separate from unit conversions
Calculator
any consistent basis
same basis as C₁
Result
V₂4 L
Added solvent3 L
Formulas
Dilution equation
C₁ × V₁ = C₂ × V₂
Solve for C₁
C₁ = C₂ × V₂ / V₁
Solve for V₂
V₂ = C₁ × V₁ / C₂
Added solvent
V_added = V₂ − V₁
Diagram
Worked example
You have 1 L of solution at concentration 100. You want to dilute to concentration 25. What final volume is needed, and how much solvent do you add?
- 01C₁ = 100, V₁ = 1 L, C₂ = 25
- 02V₂ = C₁ × V₁ / C₂ = 100 × 1 / 25
- 03V₂ = 4 L
- 04Added solvent = V₂ − V₁ = 4 − 1 = 3 L
Result
The final volume is 4 L. You need to add 3 L of solvent.
FAQ
Does this calculator handle pH dilution?
No. pH dilution involves logarithmic acid–base equilibrium and is not a simple C₁V₁ = C₂V₂ relationship. This calculator is for simple concentration dilution only.
Does this model chemical reactions during dilution?
No. This assumes no reaction occurs. If dilution triggers precipitation, heat release, or other reactions, additional modelling is required.
What concentration units should I use?
Any consistent basis — g/L, mg/L, %, ppm, etc. The calculator uses C₁V₁ = C₂V₂ with the assumption that both concentrations are on the same basis. No unit conversion is applied to concentrations.
Does this assume additive volumes?
Yes. For most aqueous dilutions this is a reasonable approximation. For systems with significant volume-of-mixing effects (e.g., concentrated ethanol–water), this assumption introduces error.