OD600

Estimate cell concentration from OD600, or calculate how to dilute a culture to a target OD.

Estimate cells/mL
Dilute to target OD (OD₁·V₁ = OD₂·V₂)

Preset(cells/mL per OD=1)

Using factor: 800,000,000 cells/mL per OD600=1

OD600 reading

Dilution factor1 = undiluted, 10 = 1:10, etc.

Also calculate total cells in a sample volume

Sample volume

Corrected OD600: 0.6

Estimated concentration: 480,000,000 cells/mL

Total cells in sample: 480,000,000 cells

Note: OD→cells/mL is an estimate and varies by strain, instrument/path length, media, and growth phase. Use your lab’s calibration curve if available.