How dilution calculator works
Dilution always follows one equation: C1V1 = C2V2, where C1 is the stock concentration, V1 is how much stock you take, C2 is the target concentration, and V2 is the final volume after topping up with solvent. The product "concentration × volume" is the amount of solute, and dilution never changes it — you only add solvent. That single conservation fact is why any three of the four numbers determine the fourth.
Enter any three of the four fields and leave the unknown blank. The tool solves C1V1 = C2V2 for the missing quantity and shows the dilution factor — how many times stronger the stock is than the working solution (equivalently, the ratio V2/V1). A 10 M stock brought down to 0.5 M is a 20× dilution, so you take one part stock and add 19 parts solvent.
Concentrations can be molar, mg/mL, percent, or any other unit, and volumes can be litres, millilitres or microlitres — the math is unit-agnostic as long as the two concentrations share a unit and the two volumes share a unit. The output also reads as a recipe: measure V1 of stock, then dilute to a final volume V2 (not dilute by adding V2 of solvent — the volumes are not always additive to better than a few percent).