Minimum defence frequency (MDF)
The share of your range you must continue with (call or raise) against a bet so that the opponent cannot profit by bluffing any two cards. MDF = pot ÷ (pot + bet).
Frequently asked questions
What is minimum defence frequency?
The share of your range you must continue with against a bet so that a bluff with any two cards would not show a profit. Against a half-pot bet it is two-thirds; against a pot-sized bet, one half.
How is MDF calculated?
Pot divided by pot plus the bet. A bet of 50 into 100 gives 100 ÷ 150, or about 67% — so folding more than a third of the time against that bet makes bluffing automatically profitable for the opponent.
Should you always defend at MDF?
No. MDF assumes the opponent can bluff with anything, which is rarely true — against a player who only bets strong hands, folding far more than MDF is correct. It is a baseline to notice when you are over-folding, not a quota to meet.