What is Minimum Defense Frequency in Poker?

Minimum defense frequency (MDF) describes the portion of your range with which you must continue when facing a bet in order to remain unexploitable by bluffs. In other words, MDF is the minimum percentage of time you must call (or raise) to prevent your opponent from profiting by always bluffing you.

The formula to calculate MDF is simple:

pot size / (pot size + bet size)

Then, multiply the answer by 100 to express it as a percentage.

For example, suppose I bet $100 into a pot of $100 and it is your turn to act. Your minimum defense frequency in this situation is:

$100 / ($100 + $100) = 0.50 or 50%

Thus, you must call or raise with at least 50% of your range to remain unexploitable by bluffs.

Want to learn more about the applications of the minimum defense frequency in poker? Read this guide:

How to Make the Most Profitable Decision Against Any Bet Size [2nd Edition]