Poisson Distribution Calculator
Math ToolsChance of k events in a fixed time or space
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History
All history →Poisson Distribution Calculator — at a glance
Find the chance of a given number of random events.
λ = 3
k = 5
Calculate
P(X = k)
How to use it — step by step
The average number of events (λ) and k.
1
Enter your values
Fill in the fields. Default numbers are shown so you can see how it works.
2
Press Calculate
The answer appears at once as large result cards.
3
Copy or share
Copy the result, or share a link that opens with your numbers filled in.
Pro tips
Small things that make the result better.
✦Events must be random and independent.
✦λ is the average count per interval.
✦Good for calls per hour or defects per batch.
Quick facts
Freeno signup
Privateruns in your browser
Instantresult in a second
No limituse it as often as you like
Frequently Asked Questions
What is λ?+
The expected average number of events in your time or space interval.
When is Poisson used?+
For counting rare, random events such as arrivals, errors or accidents.
Is my data safe?+
Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.
Is this tool really free?+
Yes — completely free, no signup, no watermark and no usage limit.
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