Dilution Calculator

About Dilution Calculator

This calculator solves C1 times V1 equals C2 times V2 for whichever of the four quantities you do not know. It is the everyday bench calculation for turning a stock solution into a working concentration, and when you solve for stock volume it also tells you how much diluent to add to reach the final volume.

How to use it

1. Choose the unknown in the Solve for menu: stock concentration, stock volume, final concentration or final volume.
2. Pick a Conc. unit and a Volume unit. They label the fields and the answer.
3. Type the three known values into the enabled boxes. The solved field is read-only and fills in automatically.
4. Read the Result panel. When solving for stock volume, an Add diluent (V2 minus V1) line appears as well.

Making 100 uL of 1 mM from a 10 mM stock

C1 = 10 mM, C2 = 1 mM, V2 = 100 uL, solve for V1

V1 = 10 uL of stock, plus 90 uL diluent

When to use it

• Preparing a working primer solution from a concentrated stock.
• Diluting a 10X buffer or 100X supplement to 1X, using X as the concentration unit.
• Working out what final concentration results when a known volume of stock goes into a larger volume.
• Finding how much stock is needed for a reagent that is added to a whole batch of tubes.

Questions about Dilution Calculator

Does the calculator convert between units?

No. The unit menus are labels only. Enter both concentrations in the same unit and both volumes in the same unit, or convert first, because the equation is a plain ratio.

What does the tool do when I ask for an impossible dilution?

It does not warn you. If the final concentration is higher than the stock, the stock volume comes out larger than the final volume and the diluent goes negative. That is a sign the target cannot be reached by dilution.

Why does the result show a dash?

A divide-by-zero, for example solving for a volume when the matching concentration is zero or blank. Empty fields count as zero.

Can it do serial dilutions?

Not in one step. Run it once per stage, using each stage's result as the next stock, or work out the overall factor as the product of the stage factors.

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