How to use the MDF calculator
- Enter the pot before your opponent bet.
- Enter their bet, or tap a quick size.
- Read how much of your range you must continue with, and how often their bluff needs to work.
What is minimum defense frequency?
Minimum defense frequency (MDF) is the share of your range you need to continue with against a bet so that your opponent cannot profit by bluffing with any two cards. Its mirror image, often called alpha, is how often a pure bluff needs to work.
MDF = pot ÷ (pot + bet) · Alpha = bet ÷ (pot + bet)
Example: the pot is $60 and your opponent bets $30. MDF = 60 ÷ 90 = 66.7%. Fold more than a third of your range and their bluffs make money.
MDF by bet size
| Bet | MDF | Bluff needs | Equity to call |
|---|---|---|---|
| 25% pot | 80% | 20% | 16.7% |
| 33% pot | 75% | 25% | 20% |
| 50% pot | 66.7% | 33.3% | 25% |
| 75% pot | 57.1% | 42.9% | 30% |
| Pot | 50% | 50% | 33.3% |
| 2x pot | 33.3% | 66.7% | 40% |
MDF vs pot odds
Pot odds tell you how often your hand needs to win to call. MDF tells you how much of your range needs to continue. They answer different questions: one is about a single hand, the other about your overall strategy.
When to ignore MDF
MDF assumes a balanced opponent. Most low-stakes players under-bluff, especially with big bets, so folding more than MDF is often correct. Against aggressive players who over-bluff, defend more.
Read more: What is MDF in poker?