Minimum defence frequency (MDF) in poker
Minimum defence frequency (MDF) is how often you need to call or raise against a bet so that your opponent can’t profit by bluffing with any two cards. The formula is pot ÷ (pot + bet). It’s a useful theory number, but at low stakes, where players bluff less than they should, you can often fold more than MDF says.
The formula
Section titled “The formula”MDF = pot ÷ (pot + bet)
Example: the pot is $100, your opponent bets $50. MDF = 100 ÷ 150 = 67%. You’d need to continue with about two-thirds of your range to stop a pure bluff from profiting automatically.
MDF by bet size
Section titled “MDF by bet size”| Bet size | MDF (continue at least) | Bluff must work (opponent) |
|---|---|---|
| 1/4 pot | 80% | 20% |
| 1/3 pot | 75% | 25% |
| 1/2 pot | 67% | 33% |
| 2/3 pot | 60% | 40% |
| Pot | 50% | 50% |
| 2× pot | 33% | 67% |
The right column is the same maths from the bettor’s side: see when to bluff.
How to use MDF
Section titled “How to use MDF”- It tells you roughly how wide to defend against balanced opponents, for example in the big blind.
- Against small bets, folding too much is a big leak: a 1/3-pot bet asks you to continue 75% of the time.
Why not to follow it blindly
Section titled “Why not to follow it blindly”- MDF assumes your opponent bluffs at the right frequency. Many low-stakes players bluff much less, especially on the river: then folding more is correct. See river play.
- Against maniacs, defend even more than MDF. See aggressive players.
- Your own hand’s equity and pot odds still decide each individual call.
What is MDF in poker?
Section titled “What is MDF in poker?”Minimum defence frequency: how often you must continue against a bet so bluffs don’t automatically profit.
What is the MDF formula?
Section titled “What is the MDF formula?”Pot divided by pot plus bet.
What is the MDF against a half-pot bet?
Section titled “What is the MDF against a half-pot bet?”About 67%.
Should beginners always follow MDF?
Section titled “Should beginners always follow MDF?”No. Against players who rarely bluff you can fold more; against maniacs you should defend more.