Understand the relationship
The reasoning behind the result
A parent fraction is not necessarily a dilution factor
Taking one fifth of the parent suspension transfers one fifth of its suspended cells under a uniform-mixing assumption. The new concentration also depends on the destination volume. A 1:5 parent split is a fivefold concentration dilution only if the destination final volume equals the original parent volume.
This distinction matters when source and destination vessels use different working volumes. The calculator keeps the transferred fraction, added medium and resulting concentration separately labelled.
Track every destination against the same source
Vused = vessels × Valiquot; Vremaining = Vparent − Vused
Each destination receives the entered parent fraction independently. If the combined allocations exceed the parent suspension, the plan is impossible and is rejected. Equal division of the complete suspension automatically makes the fraction one divided by the destination count.
Remaining parent volume is unallocated material, not an instruction to retain, discard or reculture it. The entered concentration must describe the actual mixed suspension being allocated.
Volume arithmetic cannot establish culture conditions
This calculation does not convert confluency into a cell count or recommend a passage ratio. Adherent-cell recovery, clumping, viability, attachment and growth after transfer are outside the balance.
A destination concentration is the immediate arithmetic concentration after mixing. It is not a forecast of later population, viability or readiness for an experiment.
Follow the numbers
Two quarter-parent allocations
- The parent contains 8 mL at 800,000 cells/mL, or 6,400,000 cells.
- A 1:4 parent fraction gives 2 mL and 1,600,000 cells per destination. Two destinations use 4 mL; 4 mL remains.
- Bringing each aliquot to 5 mL requires 3 mL medium and gives 320,000 cells/mL.
Each destination receives one quarter of the parent cells, but the concentration dilution is 5/2 = 2.5-fold.
Quick guide
How to use this calculator
- Enter the well-mixed suspension available after any preparation losses.
- Choose a parent fraction for each vessel or equal division of the entire suspension.
- Enter destination count and final volume per vessel.
- Inspect the stock allocation, remaining parent volume and dilution in each destination.
Calculation method
Calculation and interpretation
Separate the fraction of a parent suspension transferred from the dilution in each destination vessel.
Aliquot per vessel = parent volume/n; cells per vessel = aliquot × parent concentration; destination concentration = cells/final volume
Worked example
Two quarter-parent allocations
Each destination receives one quarter of the parent cells, but the concentration dilution is 5/2 = 2.5-fold.
Aliquot per vessel = parent volume/n; cells per vessel = aliquot × parent concentration; destination concentration = cells/final volume
Supported inputs
Precision and limits
An entered laboratory plan
This tool reconciles the measurements and choices you enter. It does not select a biological protocol, certify a preparation, assess sample suitability or establish an equipment operating limit.
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