Poker Equity & OddsMinimum defense frequency, simply
Short answer
MDF is the share of your hands you must continue with so a bluff cannot print money: pot divided by pot plus bet. Against a half-pot bet it is 66.7%, against a pot-size bet 50.0%. It is a floor for a balanced game, not a command to call. Poker Equity & Odds teaches the counting side of it in Unit 5.
The formula and a table
| Bet you face | MDF | Bluff breaks even at | Your call needs |
|---|---|---|---|
| 1/4 pot | 80.0% | 20.0% | 16.7% |
| 1/3 pot | 75.0% | 25.0% | 20.0% |
| 1/2 pot | 66.7% | 33.3% | 25.0% |
| 2/3 pot | 60.0% | 40.0% | 28.6% |
| 3/4 pot | 57.1% | 42.9% | 30.0% |
| Pot | 50.0% | 50.0% | 33.3% |
| 1.5x pot | 40.0% | 60.0% | 37.5% |
| 2x pot | 33.3% | 66.7% | 40.0% |
MDF and the bluff are the same fraction
A half-pot bluff risks 50 to win 100, so it has to work 33.3% of the time. If you fold more than that, the bluff makes money with any two cards. Continue with 66.7% of your hands and it doesn't. The two numbers add up to 100 at every bet size; the call price in the last column is a different question, about one hand against one bet.
Fold two thirds and I bluff you all day.
When not to use it
MDF assumes a player who bluffs about the right amount. Against someone who only bets with a hand, it tells you to call too much. Against someone who fires at every pot, it tells you to fold too much. Use it as the starting line when you know nothing, then move with what you see.
The call price, in Decide
Decide gives the other side of the table: what your one hand needs against this one bet. MDF is about the whole range; the price is about the hand you hold.
Questions
What is MDF in poker?
Minimum defense frequency: the share of your range that has to continue so a bluff cannot show a profit. Pot divided by pot plus bet: against a half-pot bet 66.7%, against a pot-size bet 50.0%.
Is MDF the same as pot odds?
No. Pot odds are the caller's price, bet / (pot + bet + call): 25.0% against half pot. MDF is pot / (pot + bet): 66.7%. One is about your hand, the other about your range.
Should I always defend the MDF?
No. It is a floor for a balanced game against a player who bluffs the right amount. Against someone who never bluffs, fold more; against someone who bluffs too much, call more.
What is the bluff-to-value side of it?
The bettor's side of the same fraction: a half-pot bluff has to work 33.3% of the time to break even, a pot-size bluff 50.0%.
Where the numbers come from. Every figure on this page comes from the app's own engine, the code that runs on your phone. Outs come from the Outs & Odds tool, hit chances are exact counts, and equities count every runout with no sampling. Engine build 18a5e00d. More worked numbers: flush draw odds and the pot odds cheat sheet.
