Poker MDF Chart
How often must you continue when facing a bet so a pure bluff can't print money? This minimum defense frequency (MDF) chart gives the answer for every common bet size from 25% pot to a 2× overbet. It pairs with the fold equity chart: the folds a bluff needs and the defender's MDF always add to 100%.
Minimum defense frequency chart by bet size
| Bet size (of pot) | MDF (must continue) | Folds a pure bluff needs | Bet into a $100 pot |
|---|---|---|---|
| 25% | 80% | 20% | $25 |
| 33% (⅓) | 75% | 25% | $33 |
| 50% (½) | 66.7% | 33.3% | $50 |
| 67% (⅔) | 60% | 40% | $67 |
| 75% (¾) | 57.1% | 42.9% | $75 |
| 100% (pot) | 50% | 50% | $100 |
| 125% | 44.4% | 55.6% | $125 |
| 150% | 40% | 60% | $150 |
| 200% (2× pot) | 33.3% | 66.7% | $200 |
MDF = pot ÷ (pot + bet). Folds needed = bet ÷ (pot + bet). They are exact complements. Numbers assume a pure bluff (zero equity when called) heads-up.
The formula
MDF = pot ÷ (pot + bet)
When someone bets, they risk the bet to win the pot. If you fold more often than bet ÷ (pot + bet), every pure bluff shows a profit. Defending at least MDF of the time makes those pure bluffs break even or worse. A half-pot bet needs you to continue two-thirds of the time (66.7%). A pot-sized bet needs half. A 2× overbet needs only one-third — which is why overbets punish wide calling ranges and why you should tighten up against them.
Notice the complement: folds needed = 1 − MDF = bet ÷ (pot + bet). The same number the aggressor reads on the fold equity chart is 100% minus the number on this page. Pick either view; the math is identical.
Worked example: $100 pot, $50 bet
The pot is $100 and your opponent bets $50, half the pot.
- MDF: 100 ÷ (100 + 50) = 66.7%. You must continue with about two-thirds of your range.
- Folds a pure bluff needs: 50 ÷ 150 = 33.3%. If you fold more than a third of the time, every pure bluff prints.
- Check: 66.7% + 33.3% = 100%.
Now raise the size to $75 into the same $100 pot. MDF drops to 100 ÷ 175 = 57.1%, and the bluff needs 42.9% folds. Bigger bets let you fold more, but only if his range is still full of air. Against a value-heavy player, folding to MDF still loses money because his "bluffs" aren't bluffs.
Plug the same spot into the free bluff calculator from the aggressor's side: a pure bluff into a player who folds 40% (above the 33.3% break-even) shows a profit.
What MDF leaves out
Equity when called. MDF is built for pure bluffs. Semi-bluffs with outs need fewer folds to show a profit, so the "correct" defense against a draw-heavy barrel is higher than textbook MDF — you have to deny his equity, not just his fold equity.
Exploit vs GTO. MDF is the frequency that makes a pure bluff break even. If this opponent under-bluffs, fold more. If he over-bluffs, call more. The chart is a baseline, not a law.
Multiway pots. A bluff has to get every opponent to fold. Two players each folding 40% still leave the bluff winning only 16% of the time (0.4 × 0.4), so each player's MDF is higher than the heads-up number.
Raises and future streets. Continuing includes raising. A raise that folds out his air changes the effective defense, and flop/turn decisions spill into later streets the single-street chart can't see.
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What is minimum defense frequency (MDF) in poker?
Minimum defense frequency is how often the defender must continue (call or raise) so a pure bluff is not automatically profitable. It equals pot ÷ (pot + bet). Facing a pot-sized bet, MDF is 50%.
How do you calculate MDF?
Divide the pot by the pot plus the bet: pot ÷ (pot + bet). Equivalently, 1 ÷ (1 + bet/pot). A $50 bet into $100 has MDF = 100 ÷ 150 = 66.7%.
What is the difference between MDF and fold equity?
They are complements. Fold equity's required fold % for a pure bluff is bet ÷ (pot + bet). MDF is pot ÷ (pot + bet). Add them and you get 100%. If a bluff needs 33.3% folds, the defender's MDF is 66.7%.
Should I always defend at MDF?
No. MDF assumes a pure bluff with zero equity when called, and an opponent who is balanced. Real defense also depends on your equity when you continue, stack depths, and how often he actually bluffs. Against a nit who rarely bluffs, fold more than MDF suggests.
Does MDF change in multiway pots?
Yes. Everyone has to fold for a bluff to win, so the required fold % is lower per player and each player's MDF is higher. The heads-up chart overstates how often you can fold multiway.