Solution Dilution Calculator

How it is calculated

Dilution only changes the amount of solvent, not the amount of dissolved substance, so the amount stays the same before and after: C1 × V1 = C2 × V2. The tool rearranges this to V2 = C1 × V1 ÷ C2, where C1 is the starting concentration, V1 the volume of stock solution you take, and C2 the concentration you want. C1 and C2 must use the same unit (M, %, mg/mL, whatever you have). V1 and the answers are in millilitres. It also gives the solvent to add: V2 − V1. C2 must be above zero. Pick a C2 lower than C1 for a real dilution, since a higher C2 gives a negative amount to add. Volumes are assumed to be additive.

Common mistakes

• Adding the full final volume of solvent. The answer to add is V2 − V1, because the stock already supplies V1.
• Mixing units for C1 and C2, such as molar for the stock and millimolar for the target.
• Entering V1 in litres. The tool labels the results in mL, so use mL throughout.
• Entering a target stronger than the stock. C2 higher than C1 cannot be reached by dilution and gives a negative solvent amount.
• Not topping up to the final volume. Add solvent to the mark in a volumetric flask rather than adding a measured amount on top, as some liquids do not mix volume-for-volume.