Dilution Calculator

It is the dilution equation. C1 is your stock concentration, V1 is the volume of stock you take, C2 is the final concentration you want, and V2 is the final total volume after dilution. Because the amount of solute stays the same, the product of concentration and volume is conserved on both sides.

Select solve-for V1, then enter C1, C2, and V2. The calculator returns V1 = (C2 * V2) / C1. The diluent line tells you how much solvent to add: V2 minus V1.

Any units work as long as C1 and C2 share the same concentration unit (such as mol/L, percent, or mg/mL) and V1 and V2 share the same volume unit (mL, L, or microliters). The equation does not care which units you pick, only that they match on each side.

A V1 larger than V2 would mean you need more stock than fits in your final volume, which is physically impossible. If you see this rejection in solve-for V1 mode, your target concentration C2 is too close to or larger than your stock C1. Use a stronger stock or lower your target concentration.

The dilution factor is V2 divided by V1, or equivalently C1 divided by C2. A factor of 10 (often written 1:10 or 10x) means you diluted the stock ten-fold: one part stock for every nine parts diluent, for ten parts total.