Dilution calculator (C1V1 = C2V2)
Choose the unknown and fill in the other three values, using one concentration unit and one volume unit throughout. Common when diluting a stock solution.
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How to use it
- Enter solve for, c1 stock concentration, v1 stock volume, c2 final concentration and v2 final volume.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
C1 × V1 = C2 × V2, so V1 = C2V2 ÷ C1; dilution factor = C1 ÷ C2; solvent to add = V2 − V1.
Example
Inputs: Solve for = V1 stock volume, C1 stock concentration = 10, C2 final concentration = 1, V2 final volume = 100. Result: V1 stock volume: 10; Dilution factor: 10; Solvent to add (V2 − V1): 90.
Limits and caveats
- Use the same unit for both concentrations and for both volumes; the answer comes out in that unit.
- Some liquids, such as ethanol and water, do not add up exactly in volume, so fill to the mark.
Questions about this tool
How do I make 100 mL of 1 M from a 10 M stock?
Take 10 mL of stock and make it up to 100 mL, which means adding about 90 mL of solvent.
Can I use percent instead of molarity?
Yes, as long as both concentrations are in the same unit, such as % or mg/L, because the equation is a ratio.
What does a 1:10 dilution mean?
A dilution factor of 10: one part of stock in a final volume of 10 parts.