Poisson Probability: λ = 1, k = 0 (No Events)
When the average event rate is 1 per interval, the probability of exactly zero events occurring is approximately 36.8%.
How to use this tool
- Enter rate (λ) and events (k) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your p(x = k) and the full breakdown beneath it.
Find the Poisson probability of no events in an interval when the expected rate is 1 event per interval.
Frequently asked questions
- When should I use the Poisson distribution?
- Use Poisson when counting events in a fixed interval of time or space, where events occur independently at a known average rate λ. Examples: emails per hour, accidents per week, typos per page.