# Cumulative Poisson Probability Calculator

Compute cumulative probabilities for a Poisson outcome, given the expected number of event occurrences per interval, the total number of events observed, and the total number of intervals. The calculator will compute P(K<k), P(K≤k), P(K>k), and P(K≥k) for the total number of observed event occurrences *k*. Knowing the cumulative probabilities for a Poisson outcome is often very useful in analytics studies that use Poisson experiments.

Please provide the necessary values, and then click 'Calculate'.