Calculateur de Poisson Probability
Calculate the Poisson probability of observing exactly k events given an average rate λ.
Formula and method
This calculator computes Probability directly in your browser without sending data to an external server.
Mathematical formula
- Probability:
(() => { if(lambda===0)return k===0?1:0;let logFactorial=0;for(let i=2;i<=k;i++)logFactorial+=Math.log(i);return Math.exp(k × Math.log(lambda)-lambda-logFactorial); })()
Variables and parameters
- Average rate (λ) (lambda): default value 4.
- Number of events (k): default value 2.
Some formulas are undefined for certain input combinations (such as division by zero or logarithms of non-positive numbers). In those cases the live tool displays an alert instead of NaN.
Embed this tool
Paste this snippet into your own site or blog post to embed a live, working copy of this tool. It links back to the full page on SpecWhale.
Frequently asked questions
What equation and variables does Poisson Probability Calculator use?
Poisson Probability Calculator evaluates outputs such as <strong>Probability</strong> based on inputs including Average rate (λ), Number of events. Check the Mathematical Method section for the explicit formula.
What happens if I enter invalid or zero values into Poisson Probability Calculator?
If an input combination is mathematically undefined (such as division by zero or negative square roots), SpecWhale alerts you gracefully rather than returning invalid NaN outputs.
Are my calculations in Poisson Probability Calculator saved or private?
All calculations are 100% private and run locally in your Web browser. Your numbers are never uploaded to any server, but can be saved locally to your device or exported as CSV/JSON.
Is Poisson Probability Calculator free to use?
Yes. Poisson Probability Calculator is completely free, has no usage limit, and does not require an account, email, or API key.
Does Poisson Probability Calculator store or upload my data?
No. Poisson Probability Calculator calculates everything locally in your browser. Nothing you type is sent to a server or stored by SpecWhale.
How accurate is Poisson Probability Calculator?
Poisson Probability Calculator uses a standard formula (see the Method section above for the exact expression). For high-stakes financial, medical, or legal decisions, confirm the result with a professional or an authoritative source before relying on it.
Can I embed Poisson Probability Calculator on my own website?
Yes. Use the "Embed this tool" snippet on this page to add a free, working copy of Poisson Probability Calculator to your own blog post or page.