Calculator
CFU/mL Calculator
Calculate viable colony-forming units per milliliter from a plate count.
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All fields required unless notedEnter your values and press Calculate to see the result.
Formula & Clinical Notes
Formula
CFU/mL = Colonies × Dilution factor / Volume plated (mL)
Clinical Notes
CFU/mL = (number of colonies × dilution factor) / volume plated. Count plates with 25–250 colonies for reliable results; multiply by the reciprocal of the dilution (e.g., a 10⁻⁴ dilution has a factor of 10,000) and divide by the volume plated.
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