Dilution Calculator (C₁V₁ = C₂V₂ & Serial)
Solve C₁V₁ = C₂V₂ for stock volume, final concentration or final volume with the diluent to add, or plan a serial dilution tube by tube with each concentration.
The volume of stock to pipette and the diluent to make it up with — or a tube-by-tube serial dilution table — with the dilution factor and the equation shown.
Example: To make 250 mL of 0.5 M from a 10 M stock, C₁V₁ = C₂V₂ gives V₁ = 12.5 mL of stock plus 237.5 mL of diluent (a 1:20 dilution). Four 1:10 serial steps from 1 M reach 0.0001 M.
The amount of solute
does not change.
Why C₁V₁ = C₂V₂ works, how a serial dilution is planned, and what the page leaves to you.
One dilution
Diluting moves solute from a small volume of stock into a larger volume of solution without adding or removing any of it, so concentration × volume is the same before and after: C₁V₁ = C₂V₂. Leave whichever of the four you want blank and the page solves for it; the diluent to add is V₂ − V₁ (final volume minus stock) and the dilution factor is C₁/C₂. Units are labels — molar, mg/mL, percent, ×-fold — and must simply be the same on both sides; the arithmetic does not care which.
Serial dilution
Very large factors are pipetted badly in one go (1 µL into a litre), so they are done in steps: each tube takes V/f of the previous one and V − V/f of diluent, where f is the factor per step (10 for 1:10). After k steps the concentration is C₀/fᵏ and the overall factor fⁿ. The table lists every tube; the page flags a single dilution whose transfer volume is under a thousandth of the final volume.
What it does not decide
It is laboratory arithmetic: it does not know your reagent, its density, or whether volumes are additive (for concentrated acids and alcohols they are not exactly), and it is not a dosing or medication tool. Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.
SOURCES
Last reviewed 19 September 2026. How results are checked: How we verify.