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Calcimator

Dilution Plating Calculator

Calculate colony-forming units per mL (CFU/mL) from colony count, dilution factor, and volume plated.

Inputs

Results

CFU/mL

1,500,000,000

Log₁₀ CFU/mL

9.18

Scientific Notation Mantissa1.5
Scientific Notation Exponent9
Colonies Counted150
How to Use This Calculator
  1. Enter Colony Count, Dilution Factor, and Volume Plated (mL).
  2. Review CFU/mL and Log₁₀ CFU/mL.
  3. Use Scientific Notation Mantissa and Scientific Notation Exponent to inform your decision.
  4. Use the chart to visualize the results and explore different scenarios by adjusting inputs.

How the result changes with Volume Plated (mL)

Volume Plated (mL)CFU/mLLog₁₀ CFU/mL
1150,000,0008.18
3.542,857,1437.63
6.523,076,9237.36
916,666,6677.22

What each input means

Colony Count
Number of colonies counted on the plate. Ideal range is 30–300 for accuracy.
Dilution Factor
Total dilution factor (e.g., enter 1000000 for a 10⁻⁶ dilution).
Volume Plated (mL)
Volume of diluted sample spread on the plate in milliliters.

How this is calculated

Formula

CFU/mL = colony count × dilution factor / volume plated (mL)

Worked example, using the default values

  1. Identify Input Parameters
    Colony Count = 150, Dilution Factor = 1000000, Volume Plated (mL) = 0.1 = 3 input(s) provided
  2. Calculate CFU/mL
    CFU/mL
    1500000000 = 1500000000
  3. Calculate Log₁₀ CFU/mL
    Log₁₀ CFU/mL
    9.18 = 9.18
  4. Calculate Scientific Notation Mantissa
    Scientific Notation Mantissa
    1.5 = 1.5
  5. Calculate Scientific Notation Exponent
    Scientific Notation Exponent
    9 = 9

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