OD600 Cell Density Calculator (E. coli) | Online Free Tool | Elysia Tools
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OD600 Cell Density Calculator (E. coli)
OD600 turbidity to cells/mL (1×10⁹ per OD default) and cell dry weight g/L (0.36 per OD, BioNumbers 109837), normalized for dilution factor and path length, with total cells/CDW from the culture volume, per-cell pg CDW, and an OD > 1 linearity flag. Editable strain-specific factors. Agilent/VectorBuilder/BioNumbers derived. Educational use only.
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Key facts
Category
Education
Input types
number
Output type
json
Sample coverage
4
API ready
Yes
Overview
The OD600 Cell Density Calculator estimates E. coli cell concentration in cells/mL and cell dry weight in g/L from a blank-corrected OD600 reading. It adjusts the result for dilution factor and cuvette path length, and can also calculate total cells, total CDW, and dry weight per cell when culture volume is provided.
When to use
Convert an OD600 measurement into an estimated E. coli concentration and biomass.
Correct readings taken from diluted samples or cuvettes with a nonstandard path length.
Estimate total cells and cell dry weight for a culture volume.
How it works
1Enter the blank-corrected OD600 reading, dilution factor, and cuvette path length.
2Set the cells-per-OD and CDW-per-OD factors, or use the default E. coli estimates of 1×10⁹ cells/mL and 0.36 g/L per OD.
3The calculator normalizes OD600 as reading × dilution factor ÷ path length, then estimates cells/mL and CDW g/L.
4Optionally enter culture volume to calculate total cells and total CDW; readings above normalized OD600 1 are flagged as outside the linear range.
Use cases
Estimate bacterial concentration during an E. coli growth experiment.
Calculate approximate biomass and total cell number before harvesting a culture.
Compare diluted OD600 measurements while accounting for path length and custom calibration factors.
Examples
1. Mid-log culture: OD600 0.5
Microbiology student
Background
A 25 mL undiluted E. coli culture is measured at OD600 0.5 in a standard 1 cm cuvette.
Problem
Estimate the cell concentration, cell dry weight, and totals for the flask.
How to use
Enter OD600 0.5, dilution factor 1, path length 1 cm, and culture volume 25 mL. Keep the default conversion factors.
Cells per OD: 1×10⁹ cells/mL; CDW per OD: 0.36 g/L.
Outcome
The estimate is 5×10⁸ cells/mL and 0.18 g/L CDW. The 25 mL culture contains approximately 1.25×10¹⁰ cells and 0.0045 g CDW.
Cells per OD: 1×10⁹ cells/mL; CDW per OD: 0.36 g/L.
Outcome
The normalized OD600 is 2.5, giving an estimate of 2.5×10⁹ cells/mL and 0.9 g/L CDW. The result is flagged above the linear range, so the sample should be diluted further.