D&D Critical Hit Probability Calculator
Calculate crit probability for standard attacks, Champion Fighter (19-20 / 18-20), Advantage, and Elven Accuracy (triple d20).
⚙️ Input Parameters
Real-Time Simulation P(Crit) = 1 - (1 - CritRange / 20)^DiceCount Tactical Analysis & Mathematical Context
In tabletop gaming, understanding the mathematical distribution behind your rolls allows you to make informed risk-reward decisions. Whether balancing spell slot usage in D&D 5e, evaluating an attack profile in Warhammer 40k, or weighing trade routes in Catan, knowing the exact probability mass function (PMF) turns guesswork into strategy.
Frequently Asked Questions
What is the crit chance with Champion Fighter and Advantage?
A Champion Fighter scoring crits on 19-20 has a 2/20 (10%) base crit chance. With Advantage (2 dice), the probability rises to 1 - (18/20)^2 = 19.0% (almost 1 in every 5 swings).
What is Elven Accuracy crit chance with 19-20 crit range?
With Elven Accuracy rolling 3 dice, the probability of at least one 19 or 20 is 1 - (18/20)^3 = 27.1% (more than 1 in 4 attacks).