MDF Calculator

What Is Minimum Defense Frequency (MDF)?

Minimum Defense Frequency tells you what percentage of your range you must continue with (call or raise) to prevent your opponent from profiting with any two cards as a bluff. If you fold more often than the MDF allows, your opponent can exploit you by bluffing relentlessly.

The Formula

MDF = Pot ÷ (Pot + Bet Size)

For a 75% pot bet, MDF = 1 / (1 + 0.75) = 57.1%. You need to defend at least 57.1% of your range.

Value-to-Bluff Ratios

The optimal betting range should contain a specific ratio of value bets to bluffs, determined by the bet size. The formula for the bluff percentage in the betting range is:

Bluff % = Bet Size ÷ (Pot + 2 × Bet Size)

For a pot-sized bet (100%), the optimal range is roughly 2:1 value-to-bluffs. For a 33% pot bet, it's closer to 4:1. Understanding these ratios is fundamental to constructing balanced GTO betting ranges.

Practical Application

While MDF provides theoretical guidelines, real poker requires adjustments. Against opponents who rarely bluff, you can fold more. Against aggressive players who over-bluff, you should defend wider than MDF suggests. Use MDF as a baseline, then adjust based on opponent tendencies and board texture.