Binomial Distribution Calculator

Calculate binomial probabilities for experiments with fixed trials and success probability.

Probability
Enter n, p, and k
P(X = k)
P(X ≤ k)
Mean (μ)
Std Dev (σ)
Variance
C(k)

Binomial Distribution

The binomial distribution models the number of successes in n independent Bernoulli trials, each with probability p of success.

Probability Mass Function

P(X = k) = C(n,k) × p^k × (1-p)^(n-k)

where C(n,k) = n! / (k!(n-k)!) is the binomial coefficient.

Key Formulas

  • Mean: μ = np
  • Variance: σ² = np(1-p)
  • Standard Deviation: σ = √(np(1-p))

Conditions for Binomial

  • Fixed number of trials (n)
  • Independent trials
  • Two possible outcomes (success/failure)
  • Constant probability of success (p)