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Dilution Calculator (C₁V₁ = C₂V₂)

Find how much stock solution and diluent to mix for a target concentration and volume, using the C1V1 = C2V2 dilution equation.

Stock solution needed
50
Diluent to add
450
Dilution factor
1:10

How it works

This uses the standard dilution equation C₁V₁ = C₂V₂: the amount of solute (the concentrated substance) doesn't change when you add diluent, only the volume it's spread through does. Solved for the unknown, the stock volume needed is V₁ = (C₂ × V₂) ÷ C₁, and whatever's left of the target volume after that is diluent (usually water): diluent volume = V₂ − V₁.

Concentration and volume are treated as plain numbers rather than a fixed unit — enter concentration as %, mg/mL, mol/L, or any consistent scale, and volume as mL, L, or any consistent scale. Since the equation is a pure ratio, any matching pair of units gives the same proportionally correct answer, so there's no metric/imperial toggle to get right.

The desired concentration can never exceed the stock concentration — diluting a solution only ever lowers its concentration, never raises it, so that combination is rejected rather than returning a negative diluent volume.

FAQ

What if I want to make a stronger solution than my stock?

You can't — dilution only adds volume, which only ever lowers concentration. To reach a higher concentration than your current stock, you'd need to start from an even more concentrated source or reduce the volume (e.g. by evaporation), which is a different calculation than this one.

What does the 'dilution factor' mean?

It's the ratio of stock concentration to final concentration, shown as 1:N — a dilution factor of 1:10 means the final solution is one-tenth as concentrated as the stock, regardless of what units or actual volume you used.

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