Cell culture

Cell seeding and split ratio

Cells needed per vessel, suspension volume and passage arithmetic

Culture vessel Number of vessels or wells Seeding density /cm² Medium volume per vessel ml Suspension concentration /ml Overage for losses %

—

—Cells per vessel

—Total cells needed

—Suspension volume

—Medium to add per vessel

Split ratio

Cells harvested cells Split ratio 1 :

—Cells per new vessel

—Vessels at the density above

The first figure follows from the split ratio; the second says how many vessels the harvest fills at the seeding density you entered above. They usually differ, and that difference is exactly why a split ratio on its own is a poor record of what happened.

Confluence to cell number

There is no general number for this conversion; confluent density differs several-fold between cell lines. Count your own line once at confluence and enter that figure here, and the estimate will be right for your line.

Density at full confluence /cm² Current confluence %

—Estimated cells present

Add your own vessel

If the vessel you use is missing, or its area differs from your supplier’s catalogue, add it here. It lives in your browser for this session; to keep it, add a row to the vessels table.

Name Growth area cm² Usual medium volume ml

The vessel areas are common nominal figures and vary by a few per cent between suppliers; check your own catalogue for exacting work. Suggested medium volumes are a range rather than a fixed value and depend on the line and the length of culture.