⚗ Aliquot

OD600 / cell density

Convert OD600 to cells per mL with a strain factor, or back-dilute a culture to a target OD.

OD600 to cells per mL

n = OD_{600} \cdot f

n	Cell density	cells/mL
\text{OD}_{600}	Optical density at 600 nm	dimensionless
f	Strain factor, cells/mL per OD	cells/mL

OD 0.6, E. coli

That culture is about 4.8 × 10⁸ cells/mL.

docs/v3

Back-dilution culture volume

V_{1} = \frac{OD _{2} \cdot V _{2}}{OD _{1}}

V_1	Culture volume to take	mL
\text{OD}_1	Current OD600	dimensionless
\text{OD}_2	Target OD600	dimensionless
V_2	Final volume	mL

docs/v3

Fresh medium volume

V_{med} = V_{2} - V_{1}

V_{\text{med}}	Fresh medium volume	mL
V_2	Final volume	mL
V_1	Culture volume to take	mL

docs/v3