| Step | Per Vessel | Total (with reserve) |
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Cell seeding volume = (target cells per vessel) / (current cell density). For suspension culture at target density Dtarget (cells/mL) in a vessel of working volume V: suspension volume to add = (Dtarget × V) / Dcurrent. Media volume = V − suspension volume. Example: seeding 5 mL at 0.3 × 106 cells/mL from a 2 × 106 cells/mL stock needs 0.75 mL suspension + 4.25 mL media.
A cell culture split ratio is the dilution factor between the current confluent culture and the new subculture. A split ratio of 1:4 means 1 part cell suspension is diluted into 4 parts total volume. Split ratio = current density / target density. Typical split ratios: adherent CHO 1:5–1:10, HEK293 1:3–1:10, primary cells 1:2–1:4, iPSCs 1:3–1:6, hybridoma suspension 1:4–1:10.
Typical seeding densities by cell type. Suspension: CHO 0.2–0.5 × 106 cells/mL, HEK293 suspension 0.3–1.0 × 106 cells/mL, hybridoma 0.1–0.3 × 106 cells/mL. Adherent: CHO-K1 1–3 × 104 cells/cm², HEK293 5–10 × 104 cells/cm², HeLa 1–2 × 104 cells/cm², MSCs 5 × 103 cells/cm², iPSCs 2–5 × 104 cells/cm².
For a 6-well plate (9.6 cm² per well, 2–3 mL working volume) at 5 × 104 cells/cm² you need 4.8 × 105 cells per well. For a 96-well plate (0.32 cm² per well, 100–200 μL) at the same density: 1.6 × 104 cells per well. Our cell plating calculator sizes the exact suspension volume, media volume, and total cells needed for any vessel, accounting for 10–15% pipetting reserve.
Total cells needed = target density × working volume × number of vessels + pipetting reserve. Example: seeding 10 T75 flasks (15 mL each) at 0.3 × 106 cells/mL in suspension needs 0.3e6 × 15 × 10 = 4.5 × 107 cells, + 10% reserve = 5.0 × 107. At a stock of 2 × 106 cells/mL, that is 25 mL of suspension.
Cell counting determines how many viable cells are in your current suspension using a hemocytometer or automated counter. Outputs: cells/mL and viability %. Cell seeding uses that density to calculate how much suspension to transfer into new vessels to achieve a target seeding density. Typical workflow: trypsinise confluent flask → count (cell counting calculator) → seed new vessels (this tool).
Split ratio and seeding density are two ways of expressing the same passage operation. Split ratio = current density / target density. A 1.2 × 106 cells/mL confluent flask split 1:4 starts the new culture at 0.3 × 106 cells/mL. Our cell culture split ratio calculator accepts either input and computes the other automatically.
A full cell seeding calculation follows four steps. (1) Pick a target seeding density: CHO suspension 0.3 × 106 cells/mL, HEK293 adherent 5–10 × 104 cells/cm², MSC 5 × 103 cells/cm² (verify against your supplier datasheet). (2) Compute total cells needed = target density × working volume (suspension) or surface area (adherent) × vessel count + 10–15% pipetting reserve. (3) Compute suspension volume = total cells / current measured density. (4) Media volume = working volume − suspension volume. Example for calculating seeding density in cell culture: ten T75 flasks (15 mL) at 0.3 × 106 cells/mL from a 2 × 106 cells/mL stock = 4.95 × 107 cells (with reserve) = 24.75 mL suspension + 125.25 mL media. The calculator above does all four steps automatically.
Yes. Whether you spell it hemocytometer (US) or haemocytometer (UK), the workflow is the same: count your cells using a Neubauer-improved chamber and our companion Cell Counting Calculator (returns viable cell density in cells/mL plus viability %), then paste that current density into Step 2 of this cell seeding calculator. The two calculators are designed to be used back-to-back — count first, seed second. Pipetting reserve and small-volume warnings are built in to catch errors before they cost you a passage.