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Solution Dilution Calculator

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Diluting a stock solution follows one rule: C₁V₁ = C₂V₂, where C₁ and V₁ are the concentration and volume of the concentrated stock and C₂ and V₂ are the concentration and volume after dilution. Because moles of solute are conserved, the product of concentration and volume stays the same. Pick which of the four quantities you want to solve for, enter the other three, and this calculator returns it — most often the volume of stock to pipette to reach a target concentration and volume. It also tells you how much solvent (water/buffer) to add, which is simply the final volume minus the stock volume. Concentration accepts µM/mM/M or %, volume accepts µL/mL/L; both sides use the same unit so the ratio is consistent.

Solve for

Stock volume (V₁)

10 mL

Solvent to add: 90 mL

C₁ × V₁ = C₂ × V₂

C₁V₁ = C₂V₂. Solvent to add = final volume − stock volume. Both concentrations (and both volumes) must share a unit.

How to use

  1. Choose which quantity to solve for: C₁, V₁, C₂ or V₂.
  2. Pick the concentration and volume units, then enter the three known values.
  3. Read the result and the volume of solvent to add to reach the final volume.

Frequently asked questions

What is the dilution formula?
C₁V₁ = C₂V₂. The concentration times volume of the stock equals that of the diluted solution, because the amount of solute does not change.
How much stock do I need for a dilution?
Solve for V₁ = C₂V₂ / C₁. To make 100 mL of 1 M from a 10 M stock, take 1 × 100 / 10 = 10 mL of stock and add 90 mL of solvent.
What is a dilution factor?
The ratio C₁/C₂ (equivalently V₂/V₁). A 10 M stock diluted to 1 M is a 10× (1:10) dilution.
Do the units have to match?
Both concentrations must use the same unit and both volumes the same unit, since C₁V₁ = C₂V₂ is a ratio. This tool enforces that with shared unit pickers.

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