**About Certainty Factor Calculator (Formula)**

The Certainty Factor (CF) is a mathematical concept used in artificial intelligence, specifically in rule-based expert systems, to quantify the degree of certainty that can be attributed to a particular rule or conclusion.

**The formula for calculating the Certainty Factor is:**

**CF = (MB – MD) / (1 – min(MB, MD))**

where MB is the degree of belief (represented as a number between 0 and 1) that the rule or condition is true given the evidence or observations, and MD is the degree of belief (also between 0 and 1) that the rule or condition is false given the same evidence or observations.

The term min(MB, MD) ensures that the CF is always between -1 and 1, which are the possible values of the CF. When the CF is 1, the rule is sure to be true, while if it is sure to be false, it is sure to be true. When the CF is 0, the rule is completely uncertain or unknowable.

As a result, the CF formula takes into account both degree of belief in the rule’s truth and degree of belief in its falsehood, and the numerical value provides a measure of the rule’s usefulness or reliability.