MDF Minimum Defense Frequency Calculator: GTO defense ratio floor when facing a bet. Includes formulas, exploitative adjustments, and FAQ.
MDF Minimum Defense Frequency = Pot ÷ Pot + Bet. It represents the minimum frequency at which you must call/raise when your opponent is pure bluffing, so that their bluff cannot automatically profit. This is the theoretical lower bound of GTO defense.
Example: 50% pot → MDF ≈ 67%, meaning roughly two-thirds of your range needs to continue to avoid being exploited. MDF links bet sizing with defensive width and should be understood alongside pot odds, EV, and actual range advantage, rather than applied mechanically. Use the calculator on this page to quickly determine break-even equity, then cross-reference the numbers with opponent range, position, and turn/river plans to avoid just memorizing formulas without applying them at the table. Common Misconceptions Misunderstanding MDF as "must call every hand"; ignoring position, SPR, ICM, and nut advantage. Calling too wide against polarized river bets. Using cash game MDF in tournament bubbles, leading to excessive hero calls around pay jumps. Also, don't treat solver frequencies as gospel without pot odds verification; when information is incomplete, ICM and SPR remain the first principles of tournament play. Learning Tips After each opponent bet, mentally calculate α and 1−α, then compare against your own defending combos. Memorize MDF together with pot odds and alpha as a triad; use solver screenshots to compare "theoretical MDF vs your actual fold rate" to build intuition for sizing and frequency. Each week, pick five real hand histories, recalculate using the same tool, and revisit the glossary to review automatically interlinked concepts like pot odds, ICM, and SPR.
Scenario：Pot 100, opponent bets 75.
MDF = 100 ÷ (100 + 75) = 57.1% 2. Opponent's bluff requires you to fold 42.9% to break even. 3. Context: Tool example step: mdf
GTO applying MDF's combo continues
Conclusion：At least approximately 57% of range needs to defend; during exploitation, can overcall against high-frequency bluffers.
Scenario：Pot 80, opponent bets 40, you have 8 outs.
Pot odds required equity ≈ 40/120 = 33% 2. Context: Tool example step: mdf
8 outs on turn about 16%, river total about 32% 3. Pure pot odds are insufficient; need to evaluate implied odds and position.
Conclusion：Context: Tool example result: mdf
When there are no implied odds, calling on the turn is too loose; if there are reliable implied odds or the opponent overpays, you can continue.
Scenario：Pot is 200, you consider betting 50 for thin value.
Conclusion：Thin value betting is essentially a reduced version of the pot odds problem; the smaller the sizing, the wider the required calling range.
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