Chemical Solution Dilution Calculator
Enter your stock concentration, target working concentration, and final volume. Get the exact mL of stock to measure out and solvent to add — with step-by-step plain-English instructions. Nothing uploaded.
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Learn more: dilution math (C1V1=C2V2)
C1V1=C2V2 in practice
Say you have a 500 ppm stock solution and need 2 liters at 10 ppm. Solving for the stock volume gives V1 = (C2 x V2) / C1 = (10 x 2) / 500 = 0.04 liters, or 40 mL.
The formula only gives the stock volume. The solvent is a second subtraction: 2 liters minus 0.04 liters leaves 1.96 liters to add. The calculator does both steps and lists them as measuring instructions.
The target has to be lower than the stock
A dilution can only make a solution weaker. If the target concentration is equal to or higher than the stock, the calculator shows a message instead of a result, because the maths would need at least as much stock as the final volume.
The dilution factor is the stock concentration divided by the target, so 500 ppm down to 10 ppm is a factor of 50. Put another way, 1 part stock makes 50 parts of final solution.
Final volume versus solvent volume
The final volume you enter is the total you end up with, not the amount of solvent. Measure the stock, then add solvent until the vessel reaches that total. For a few liquids the combined volume comes out slightly under the sum of the parts, which is another reason to top up to the final mark.
FAQ
What is the difference between dilution factor and target concentration?
The dilution factor is the ratio of starting concentration to target concentration (C1/C2). The target is the concentration you want to end up with. A factor of 50 tells you how much weaker the solution gets, while the target tells you where it lands.
Can I mix units, like a stock in % and a target in ppm?
No, convert both to the same unit first. C1V1=C2V2 only holds when both concentrations use one unit, and the calculator applies the single unit you pick to the stock and the target. The final volume is entered in mL.
Why does the calculator warn about acids?
When the unit is % and the stock is above 50, it shows a safety note: add concentrated acid or base to the water, never water to the acid, to avoid dangerous splashing from the heat released. Follow your lab's own safety procedures for anything hazardous.