Solve C1V1 = C2V2 for any missing value, or plan a serial dilution — how concentration falls step by step.
Leave exactly one box blank — that is the value solved for. Use the same concentration units for C1 and C2, and the same volume units for V1 and V2.
Answer
—How to use this tool
Solve one missing value, or plan a serial dilution over several steps.
Leave exactly one blank in solve mode — that is the answer.
C1 and C2 in the same units, V1 and V2 in the same units — the units cancel out.
For volume answers, the extra volume is the solvent you add.
Formula & worked example
A stock at 10 units with 5 ml made up to 50 ml gives C2 = 10 × 5 ÷ 50 = 1 unit. And a serial dilution starting at 100, diluted 1:10 three times, ends at 100 ÷ 10³ = 0.1.
Limitations — read this before you rely on it
The equation assumes volumes add and concentrations are in consistent units; it does not account for volume contraction on mixing or for activity effects in concentrated solutions. Serial steps assume each step is mixed thoroughly before the next.
Frequently asked questions
The dilution equation: the amount of solute before dilution equals the amount after. C is concentration, V is volume, 1 is before and 2 is after.
Final volume minus starting volume. Diluting 5 ml to 50 ml means adding 45 ml of solvent.
One part stock plus nine parts solvent, making ten parts total — a dilution factor of 10.
Yes — leave V1 blank and enter the rest. That tells you how much stock to start with for a target concentration and volume.
Tiny concentrations are hard to pipette accurately in one step. Several moderate dilutions reach the same result with far less error.