MDF in poker means minimum defense frequency: the share of your range that must continue against a bet so a zero-equity bluff cannot make an immediate profit. For one bet into a pot, use MDF = pot before the bet divided by the pot plus the bet. Facing a 60-chip bet into an 80-chip pot, MDF is 80 divided by 140, or about 57.1 percent.
Minimum defense frequency applies to your whole range, not one specific hand. Calls and raises both count as defenses. The percentage tells you roughly how much of the range should continue in a simplified model; it does not identify the hands that belong in that continuing group.
Use MDF as a post-session review benchmark rather than a rule that forces action. Your opponent's likely bluffing frequency, the strength and shape of both ranges, blockers, future streets, and multiway action can all justify defending more or less than the raw number.
What does MDF mean in poker?
Minimum defense frequency is the portion of a range that continues when facing a bet. Its narrow purpose is to keep a bluff with no chance at showdown from winning automatically through folds. If your range folds more often than the bettor needs, that bettor could profit by bluffing any two cards in the simplified model.
The word minimum can be misleading. MDF is not the smallest legal amount you may defend, nor a promise that matching the number produces the best strategy. It is a mathematical reference point built from the pot and bet size. Range interaction decides how useful that point is in the hand you actually played.
What is the minimum defense frequency formula?
Use MDF = pot divided by pot plus bet. Measure the pot immediately before the opponent wagers, then add that wager once in the denominator. If the pot is 100 and the bet is 50, MDF is 100 divided by 150, which is about 66.7 percent.
You can check the result from the bettor's side. A 50-chip bluff risks 50 to win the 100 already in the pot, so it needs folds 33.3 percent of the time—50 divided by 150—to break even with zero equity. The bettor's break-even fold rate and the defender's MDF are complements: 33.3 percent plus 66.7 percent equals 100 percent.
How does bet size change MDF?
A smaller bet creates a higher MDF because the bettor risks less to win the same pot. Against a one-third-pot bet, MDF is 75 percent. Against a half-pot bet, it is about 66.7 percent. Against a three-quarter-pot bet, it is about 57.1 percent. Against a pot-sized bet, it is 50 percent.
An overbet lowers the range-level target further. Facing a bet of one and a half times the pot, MDF is 40 percent because the calculation is 1 divided by 2.5. This does not mean larger bets should receive only strong calls. It means the continuing range can be narrower; choosing its members still requires hand and range analysis.
What is the difference between MDF and pot odds?
MDF asks how much of your range should continue so automatic bluffs do not succeed. Pot odds ask how much equity a particular call needs. The two numbers use the same pot and wager but answer different questions, so you should not swap one for the other.
Suppose the river pot is 80 and an opponent bets 60. MDF is 80 divided by 140, or about 57.1 percent. A call, however, risks 60 to contest a final pot of 200, so the break-even equity for that call is 60 divided by 200, or 30 percent. First decide which hands have enough equity or strategic value to continue; then check whether those calls and raises defend an appropriate share of the range.
What is a complete river MDF example?
You reach the river heads up with a range of 100 weighted combinations. The pot is 80 big blinds, and your opponent bets 60 big blinds. The MDF is about 57.1 percent, so the simplified benchmark is to continue with roughly 57 of those 100 combinations and fold roughly 43.
That 43-percent fold region matches the price of the bluff. The bettor risks 60 to win 80 and therefore needs you to fold more than 60 divided by 140, or about 42.9 percent, for a zero-equity bluff to profit immediately. Defending about 57.1 percent holds those automatic bluffs to their break-even point before other strategic details are added.
Now sort the 100 combinations instead of calling with the first 57 you can name. Clear value hands may raise or call. Strong bluff-catchers can call. Some hands with useful blockers may rank above hands with similar raw strength, while the weakest bluff-catchers and missed draws can fold. Mixed decisions may split a combination between continuing and folding, which is why weighted combinations are more precise than a rigid hand count.
Do raises count toward minimum defense frequency?
Yes. A defense means any continuation that prevents the bettor from winning the pot immediately. Both calls and raises do that. If a range continues 45 percent by calling and 12 percent by raising, its total defense frequency is 57 percent.
Do not add raises on top of an already complete calling target. If MDF is 57 percent, that is the combined continue region, not 57 percent calls plus a separate raising range. Build the strongest or most suitable raises first, place the appropriate calls below them, and let the remaining range fold.
Which poker hands should make up the defending range?
Begin with the range that actually reached the decision. Rank its combinations by how well they perform against the opponent's betting range, not by their absolute hand labels. A modest pair can be a sensible bluff-catcher in one line and an easy fold in another because the value hands and missed draws are different.
Use blockers only after identifying those value and bluff regions. A card that removes likely value bets can improve a call; a card that removes missed draws can make the same-looking hand worse. Then consider whether a raise earns value from worse, folds out better, or simply turns a hand with adequate calling value into an unnecessary bluff.
Does MDF work before the river?
You can calculate the same benchmark on the flop and turn, but interpreting it is harder. A bluff may still improve, a call may not realize all of its equity, and both players can make more bets later. Those branches mean the immediate zero-equity-bluff model leaves out important value.
Treat earlier-street MDF as an orientation point. Check the price, remaining stack, position, board, and likely future action before deciding which draws, made hands, and raises continue. On the river, with no cards left to come, the relationship between the bet, folds, and bluff-catchers is usually easier to isolate.
When should you defend more or less than MDF?
Defend less when the betting range is too value-heavy for your marginal hands to meet their price. Matching a theoretical percentage does not rescue calls that lose against the range you actually assign. If a player arrives with few plausible bluffs and rarely turns them into bets, folding more bluff-catchers can be a deliberate adjustment.
Defend more when the betting range contains more bluffs than the price requires, or when your range interacts especially well with the line. Also be careful in multiway pots: the simple MDF formula describes one bettor against one defending range. With multiple players behind or multiple ranges able to continue, one heads-up percentage does not allocate the table's defenses for you.
What are the most common MDF mistakes?
The first mistake is applying MDF to one hand: “This hand is above 57 percent, so I must call.” The percentage belongs to the full arrival range. The second is counting only calls and forgetting raises. The third is using the pot after the bet as the numerator, which inflates the defense target.
Another mistake is assuming the benchmark must be reached in every spot. MDF does not prove the opponent bluffs enough, construct your range, account for players still to act, or solve future streets. It is most useful when it reveals a question: Are you folding an entire hand class too readily, or are you correctly departing from the benchmark because the betting range is unbalanced?
How can Tells help you review MDF after a hand?
After a completed hand, Tells Poker Replay keeps the positions, cards, stacks, pot, wagers, and action in sequence. Pause at the bet you want to study, confirm the pot immediately before it, and compare the wager with that pot before calculating the range-level defense target.
The current iOS analysis pipeline also computes deterministic postflop decision metrics from the recorded action, including MDF alongside Pot Odds and SPR. Use those checked numbers as the start of a structured second opinion, then question the ranges and assumptions behind the decision. Tells is for post-session study, not assistance during live action, and its debrief is not a perfect or definitive answer.
Frequently asked questions
Does MDF mean you must call?
No. MDF is a range-level benchmark, and both calls and raises count toward it. A particular hand may still fold if other combinations are better candidates to continue.
Is minimum defense frequency the same as pot odds?
No. MDF estimates how much of a range continues against a bet. Pot odds give the equity a specific call needs to break even against the bettor's range.
Can you defend less than MDF against a player who rarely bluffs?
Yes. If the betting range is more value-heavy than the break-even model assumes, folding more marginal bluff-catchers can be a reasoned adjustment. Write down that range assumption during review.
What is MDF against a pot-sized bet?
It is 50 percent. Divide the pot by the pot plus an equal-sized bet: 1 divided by 2 equals 0.5, or 50 percent.