Poisson Distribution Calculator

Calculate Poisson distribution probabilities. Enter the average rate (λ) and number of events (k) to get exact, cumulative, and upper tail probabilities.

How to Use Poisson Distribution Calculator

Enter the average rate λ (lambda) and the number of events k. The calculator computes P(X = k), cumulative probability P(X ≤ k), upper tail P(X > k), and distribution statistics including mean, variance, and standard deviation.

Step-by-Step Instructions

  1. Enter the average rate λ (lambda) — must be positive
  2. Enter the number of events k — must be a non-negative integer
  3. Click Calculate to compute all probabilities
  4. View exact, cumulative, and upper tail probabilities with statistics

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