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Dilution Calculator

Use C1V1 = C2V2 to calculate the stock volume required for a target concentration and final volume.

Reviewed/updated September 8, 2026
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Solution dilution calculator

The dilution equation C₁V₁ = C₂V₂ is used when the amount of solute is conserved during dilution. Enter the stock concentration, desired concentration and desired final volume to calculate the stock volume required.

Formula

V₁ = (C₂ × V₂) ÷ C₁.

Example

To prepare 100 mL of a 2 mg/mL solution from a 10 mg/mL stock, V₁ = (2 × 100) ÷ 10 = 20 mL stock. Dilute to a final volume of 100 mL.

Important

C₁ and C₂ must use the same concentration units, and V₁ and V₂ will then share the same volume unit. This simple equation assumes additive-volume behavior is suitable for the intended calculation.

Questions

Frequently asked questions

Can I use different concentration units?

Convert both concentrations to the same unit before applying C1V1 = C2V2.