Dilution Calculator
Diluting a stock solution? Enter any three values and the calculator solves the fourth from C₁V₁ = C₂V₂ — and tells you how much stock to pipette.
Enter any three of C₁, V₁, C₂, V₂; the fourth is solved with C₁V₁ = C₂V₂.
How the dilution equation works
When you dilute a solution, you add solvent but do not change the number of moles of solute. Because moles equal concentration times volume, the product stays constant: C₁V₁ = C₂V₂. Give the calculator any three of those four quantities and it returns the missing one.
Worked example
To make 100 mL of 0.1 M from a 1 M stock, solve for V₁: V₁ = C₂V₂ ÷ C₁ = (0.1 × 100) ÷ 1 = 10 mL of stock, then top up to 100 mL with solvent.
Always add concentrated acid to water, never the reverse.
For the full theory including serial dilutions, read dilution and serial dilution explained.
Gear for accurate dilutions
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Volumetric Flask Set (Class A)
Class A borosilicate flasks for making solutions to an exact volume.
View on AmazonFrequently asked questions
How do I use the dilution calculator?
Enter any three of stock concentration (C1), stock volume (V1), final concentration (C2), and final volume (V2). The calculator solves the remaining one using C1V1 = C2V2.
How much stock solution do I need?
Choose ‘Stock volume’ as the unknown and enter C1, C2, and V2. The result is the volume of stock to take before topping up to the final volume.
Can I mix concentration units?
Yes. Each field has its own unit selector (M, mM, µM for concentration; L, mL, µL for volume), and the calculator converts internally.