Math
Dilution Calculator
Solve C1V1 = C2V2 for any unknown. Compute stock volume, final concentration, final volume, or back-calculate stock strength.
Dilution Calculator (C1V1 = C2V2)
How much stock to take. Given C1, C2, and V2.
Any unit (mol/L, percent, mg/mL). Must match C2 unit.
Target concentration after dilution. Same unit as C1.
Total volume after dilution. Same unit as V1.
Stock volume (V1)
10
Stock concentration (C1)
10
Stock volume (V1)
10
Final concentration (C2)
1
Final volume (V2)
100
Diluent to add (V2 - V1)
90
Dilution factor (V2 / V1)
10x
Frequently Asked Questions about the Dilution Calculator
What is the C1V1 = C2V2 formula?
C1V1 = C2V2 is the conservation-of-solute equation used for dilutions. C1 is your starting concentration, V1 is the volume of stock you draw, C2 is the target concentration, and V2 is the final total volume. Because you are only adding solvent, the moles (or mass) of solute stay the same on both sides, so the two products must be equal.
How do I calculate how much stock solution to use?
Choose the "Solve for V1" mode, then enter C1, C2, and V2. The calculator returns V1 = (C2 x V2) / C1, the volume of stock to take. It also shows the diluent volume (V2 - V1), which is how much solvent you add to reach the final volume.
What units should I use for concentration and volume?
Any consistent units work. C1 and C2 must share the same concentration unit (mol/L, mg/mL, %, or anything else), and V1 and V2 must share the same volume unit (mL, L, uL, etc.). The calculator does no unit conversion, so matching units on each side is your responsibility.
Why does the calculator reject a result where V1 is larger than V2?
If the computed V1 exceeds V2, the physics breaks down: you cannot draw more stock than the final volume itself holds. This happens when your target C2 is greater than your stock C1, since dilution can only reduce concentration. Use a more concentrated stock or lower your target C2.
What is the dilution factor?
The dilution factor equals V2 / V1, which is the same as C1 / C2. A factor of 10 (written 1:10 or 10x) means one part stock is combined with nine parts diluent for ten parts total. The calculator displays this value alongside the diluent volume so you can verify the fold-change of your dilution.