μ
MICROBIOLOGY NOTES · LAB TOOLS
Microbiology Notes Lab Calculator
Professional laboratory calculation tools
FREE LAB TOOL
PLATE COUNT METHOD
CFU/mL Calculator
Calculate viable microbial concentration in liquid samples.
Average Colony Count:
87.5
FINAL RESULT
8.75 × 10⁶ CFU/mL
Average of two plate counts.
Formula: CFU/mL = Average colonies ÷ (Dilution fraction × Volume plated).
SOLID SAMPLE ENUMERATION
CFU/g Calculator
Calculate microbial concentration per gram of sample.
Average Colony Count:
78
FINAL RESULT
7.8 × 10⁵ CFU/g
Average of two plate counts.
Formula: CFU/g = Average colonies ÷ (Subsequent dilution fraction × Volume plated × Initial homogenate concentration in g/mL).
STEPWISE DILUTION
Serial Dilution Calculator
Calculate cumulative dilution across repeated transfer steps.
FINAL DILUTION
10⁻⁶
Six successive 1:10 dilutions.
| Tube | Step Dilution | Cumulative Dilution |
|---|
MICROBIAL INACTIVATION
Log Reduction Calculator
Calculate microbial reduction after treatment.
LOG REDUCTION
3.00 log₁₀
99.9% reduction.
REPLICATE PLATES
Average Colony Count
Calculate the arithmetic mean of colony counts.
AVERAGE COLONIES
85
Three observations.
DILUTION NOTATION
Dilution Factor Converter
Convert dilution exponent and reciprocal factor.
DILUTION
10⁻⁴
Fraction: 0.0001 · Denominator: 10,000
PRESENCE / ABSENCE METHOD
MPN Calculator
Estimate microbial concentration using replicate tubes.
This is a maximum-likelihood estimate.
It is not a replacement for validated MPN tables or
your laboratory SOP.
| Dilution Exponent | Positive Tubes | Total Tubes |
|---|---|---|
MPN ESTIMATE
—
Enter tube results and calculate.