Minimum defense frequency, live — set the bet size and see how often to defend, the bluff break-even, and the equity you need to call. No account, no ads.
| Bet (% pot) | MDF you defend | α bluff break-even | Min call equity |
|---|---|---|---|
| 25% | 80% | 20% | 17% |
| 33% | 75% | 25% | 20% |
| 50% | 67% | 33% | 25% |
| 66% | 60% | 40% | 28% |
| 75% | 57% | 43% | 30% |
| 100% | 50% | 50% | 33% |
| 150% | 40% | 60% | 38% |
| 200% | 33% | 67% | 40% |
MDF = pot ÷ (pot + bet): defend at least this often and no bluff shows an automatic profit. It's a default, not a law — deviate against players who never bluff (fold more) or never stop (defend less). Exploitation beats balance whenever a read is strong.
Defend too little and every bet becomes a profitable bluff against you. MDF is the exact frequency that shuts that door.
If you only continue with your strong hands, a thinking opponent can bet every single time and print money with their bluffs — you fold too often to punish them. Minimum defense frequency is the fold-line that stops that: defend at least MDF of your range (call or raise) and no bluff, however cheap, makes an automatic profit. It's the reason 'I only had ace-high, so I folded' is a leak when the bet is small.
MDF falls as the bet grows, because a bigger bluff risks more of the bettor's own chips. Against a half-pot bet you must defend about two-thirds of your range; against a pot-sized bet, only half; against a big overbet, less again. Pair MDF with the pot odds your hand is getting: MDF tells you how much of your range to keep, pot odds tell you which hands are worth a call.
Set the bet, read how much of your range to keep.
Drag the slider or tap a preset to set the bet as a percentage of the pot — the size is all MDF depends on.
The big number is the minimum share of your range you should continue with to stay unexploitable.
See how often the bluff needs to work (α) and the minimum equity your hand needs to call — the pot-odds threshold.
The pot is $100 on the river and villain bets $100 — a pot-sized bet. MDF here is pot ÷ (pot + bet) = 100 ÷ 200 = 50%, so you should continue with at least half of your range. The reason is the flip side, α: this bet only has to work half the time to break even as a bluff, so if you fold more than 50% a pure bluff prints money against you. But 'defend 50%' doesn't mean call with anything — it means keep your best 50%. Sort your range and continue with the strongest bluff-catchers: the hands that beat the bluffs you're worried about and chop or beat his thin value. Fold the bottom half — the busted draws and air that can't beat a bluff anyway. Defend the right 50% and no bluff, however bold, can auto-profit.
Verdict — defend your best 50%, and pick bluff-catchers over airFix It feels safe to fold to a tiny stab, but small bets demand you defend more, not less — a quarter-pot bet needs about 80% of your range to continue. The smaller the bet, the wider you defend.
Fix MDF assumes a balanced opponent. Against a nit who only bets value, defending 50% just pays off their strong hands — fold far more than MDF and let them win the small pots.
Fix MDF is a range frequency — what share of all your hands to keep. Pot odds are a single-hand equity question. Use MDF to decide how many hands continue, and pot odds to decide which ones clear the bar.
Fix The goal isn't to call with exactly 50% of anything — it's to keep your best 50%. Continuing with hands that can't beat a bluff defeats the entire point of the number.
Three spots. Work out the frequency, then check the reasoning.
Villain bets half the pot on the river. What is your minimum defense frequency?
MDF = pot ÷ (pot + bet) = 1 ÷ (1 + 0.5) = 66.7%. A half-pot bet is cheap for the bluffer, so you must defend about two-thirds of your range to stop it auto-profiting.
What does alpha (α) tell you?
α = bet ÷ (pot + bet) is the break-even success rate for a bluff. It's the mirror of MDF: against a pot-sized bet α is 50%, so the bluff only needs to work half the time.
You're up against a player who never bluffs on the river. How should you adjust to a pot-sized bet?
MDF only matters against opponents who bluff enough to punish you. If they never bluff, there's nothing to defend against — over-fold and only continue with hands that beat their value bets.
You scored 0 / 3. The more you drill this, the faster the maths becomes instinct.
MDF is the smallest fraction of your range you must continue with (call or raise) against a bet so that your opponent can't profit by bluffing any two cards. It equals pot ÷ (pot + bet).
Divide the pot by the pot plus the bet. Facing a pot-sized bet, MDF = 1 / (1 + 1) = 50%. Facing a half-pot bet, MDF = 1 / (1 + 0.5) = 66.7%. The smaller the bet, the more you must defend.
Alpha is the flip side of MDF: the fraction of the time a bluff must succeed to break even, equal to bet ÷ (pot + bet). If MDF is 66.7%, then α is 33.3% — a bluff that gets through more than a third of the time profits.
No. Pot odds tell you the minimum equity a single hand needs to call. MDF tells you what share of your whole range to continue with. You use pot odds to decide which hands clear the bar MDF sets.
No — MDF is a default that assumes a balanced opponent. Against players who rarely bluff you should over-fold; against players who bluff too much you should over-defend. MDF is the baseline you deviate from once you have a read.