Cell Dilution Calculator — C₁V₁ = C₂V₂
Solve any cell dilution problem using C₁V₁ = C₂V₂. Enter the three known values — initial concentration, initial volume, and target concentration or final volume — and the calculator finds the unknown.
Solve for
cells/mL
mL
cells/mL
C₁ × V₁ = C₂ × V₂
- 1
Total cells (C₁ × V₁)
1,000,000 × 1 = 1,000,000 - 2
Final volume (V₂ = C₁V₁ ÷ C₂)
1,000,000 ÷ 100,000 = 10
How does this calculator work?
Cell dilution follows C₁V₁ = C₂V₂. Rearrange for any unknown: V₂ = C₁V₁/C₂, C₂ = C₁V₁/V₂, V₁ = C₂V₂/C₁, C₁ = C₂V₂/V₁. The dilution factor is C₁/C₂; add V₂ − V₁ mL of diluent to the aliquot. Units must be consistent on both sides.
Formula
How this is calculated
Cell dilution follows the conservation of solute principle: the total number of cells before dilution equals the total number after. If C₁ is the initial concentration (cells per mL) and V₁ is the volume of stock solution taken, then C₁ × V₁ is the total number of cells in that aliquot. When this aliquot is diluted to a final volume V₂, the new concentration C₂ must satisfy C₂ × V₂ = C₁ × V₁, so any one of the four values can be found from the other three by simple rearrangement.
The dilution factor is C₁ ÷ C₂ — for example, a 1,000,000 cells/mL stock diluted to 100,000 cells/mL is a 10-fold dilution. The volume of diluent (usually culture medium or buffer) to add is V₂ − V₁; if this is positive you add diluent, if it is negative your target concentration is higher than the stock (which is not possible by dilution — you would need to concentrate the suspension instead).
This formula works for any units of concentration (cells/mL, cells/µL, CFU/mL) and any units of volume as long as the concentration and volume units are consistent on both sides. It assumes perfect mixing, no cell loss, and that the diluent is cell-free.
Frequently asked questions
Take 1 part stock (V₁ = 1 mL) and add 9 parts diluent to reach a final volume of 10 mL (V₂ = 10 mL). The resulting concentration C₂ = C₁ × (1 ÷ 10) = C₁ ÷ 10.
The dilution factor is C₁ ÷ C₂ (e.g. 10 for a tenfold dilution). The dilution ratio is V₁:V₂ expressed as parts stock to total volume (e.g. 1:10). The dilution factor equals V₂ ÷ V₁.
Yes — apply the calculator once for each step of the serial dilution. The output concentration C₂ from one step becomes the input concentration C₁ for the next. A common series is 1:10 repeated three times for a 1:1,000 overall dilution.
TG we-Calculate Editorial Team. (2026). Cell Dilution Calculator — C₁V₁ = C₂V₂ [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/cell-dilution-calculator
TG we-Calculate Editorial Team. "Cell Dilution Calculator — C₁V₁ = C₂V₂." TG we-Calculate. 2026. https://we-calculate.com/calculator/cell-dilution-calculator.
TG we-Calculate Editorial Team, "Cell Dilution Calculator — C₁V₁ = C₂V₂," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/cell-dilution-calculator
@misc{wecalculate_cell_dilution_calculator, title = {Cell Dilution Calculator — C₁V₁ = C₂V₂}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/cell-dilution-calculator}}, year = {2026}, note = {TG we-Calculate} }
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