Log Reduction Calculator
Chemistry & BiologyCalculate log reduction and percentage reduction in microorganism count from initial and final CFU counts.
Log Reduction
Log10 reduction in colony-forming units after treatment.
Percentage Reduction
99.0000
Percentage reduction in colony-forming units after treatment.
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Creators
Odeh Ahwal0people find this calculator helpful
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Saved
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Chemistry & Biology calculators
Frequently Asked Questions
What does a 1 log reduction mean?
A 1 log reduction means the microorganism count was reduced by a factor of 10, equivalent to a 90 percent reduction. Each additional log adds another factor of 10, so a 5 log reduction is a 99.999 percent reduction.
Why use log reduction instead of just percentage?
Percentage reduction alone becomes hard to read at very high effectiveness levels, since 99.9 percent and 99.999 percent look similar but represent a 100-fold difference in surviving organisms. Log reduction makes that difference immediately clear.
Where is log reduction commonly used?
Log reduction is a standard way to report the effectiveness of disinfectants, sterilization processes, water treatment, and food safety interventions against bacteria, viruses, and other microorganisms.
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