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Dilution Calculator (C1V1 = C2V2)

Solve C1V1 = C2V2 for any missing value — stock volume, final volume or concentration — and see how much solvent to add. Works with M, mM, % and any volume unit. Free for chemistry labs.

V₁ (stock volume)

25 mL
  1. 1

    Moles of solute do not change when you dilute

    C1V1=C2V2C_1V_1 = C_2V_2
  2. 2

    Rearrange for V1 and substitute

    V1=C2V2C1=0.5×1002=25V_1 = \frac{C_2V_2}{C_1} = \frac{0.5\times100}{2} = 25
  3. 3

    Solvent to add

    Take 25 of the stock and add 75 of solvent to reach 100 (same volume unit throughout). Dilution factor = 4×.

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FAQ

Why does C1V1 = C2V2 work?

Diluting adds only solvent, so the amount of solute stays the same: concentration × volume before equals concentration × volume after.

Do the units have to match?

C₁ and C₂ must use the same concentration unit and V₁ and V₂ the same volume unit; the answer comes out in those units.

How much water do I add?

Solvent to add = V₂ − V₁. The calculator shows it after solving.

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