Dilution Calculator

The formula this calculator uses

C1 x V1 = C2 x V2

C1

Concentration of the stock solution you are starting with

V1

Volume of stock solution you need to measure out

C2

Concentration you want to end up with

V2

Final volume of the diluted solution

How to check the result by hand

1. 1

   Write down the stock concentration and the one you want

   Call the stock C1 and the target C2, and make sure both are in the same unit. Five molar stock diluted to 0.5 molar is a clear pair; mixing molarity with millimolar is not.

2. 2

   Fix the final volume you want to prepare

   This is V2, the total volume of the finished solution including the solvent. Wanting 100 millilitres of dilute solution means V2 is 100, not 90.

3. 3

   Solve for the stock volume

   Multiply C2 by V2 and divide by C1. Half a mole per litre times 100 millilitres, divided by 5 moles per litre, gives 10 millilitres of stock.

4. 4

   Subtract to find the diluent

   Take the stock volume away from the final volume. Ninety millilitres of solvent brings 10 millilitres up to the 100 millilitres you wanted. Adding 100 millilitres of solvent instead would overshoot.

5. 5

   Check with the dilution factor

   Divide the stock concentration by the final one. Five divided by 0.5 is 10, so this is a tenfold dilution, and the final volume divided by the stock volume should also come to 10. Both routes agreeing is a good sign the arithmetic is right.