FREE TOOLS
Distribution Probability Calculator
Calculate normal,binomial or Poisson probabilities with explicit model parameters.
Distribution, Normal: observation, Normal: mean, Normal: positive standard deviation, Binomial: whole trials, Binomial: success probability (0–1), Binomial/Poisson: whole observed count, Poisson: mean event rate
JSON
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Enter the displayed example values,or choose the local input files requested by the controls. Optional source files take precedence where labelled.
- Choose Calculate result and inspect the complete result and any reported limitations.
- Use Download result and each companion download link to save complete outputs. Reset clears output and restores example controls.
Examples
Distribution: normal
Normal: observation: 1.96
Normal: mean: 0
Normal: positive standard deviation: 1
Binomial: whole trials: 10
Binomial: success probability (0–1): 0.2
Binomial/Poisson: whole observed count: 3
Poisson: mean event rate: 4
Limitations
- Calculate normal density and lower/upper tails,or binomial/Poisson point mass and inclusive tails at a whole count. Normal point probability is zero and differs from density. Binomial trials and Poisson rate/count magnitude are bounded by1,000,000; probabilities include0/1 and degenerate distributions. Counts outside the distribution support are valid zero-mass outcomes. Only the selected model fields are used. Download the complete JSON report. All processing stays in your browser. Combined input limit: 400,000 UTF-8 bytes, 100,000 characters per field; report limit: 4 MiB. Floating-point rounding and probability underflow can occur.
- Complete outputs only. Unsupported or oversized input is refused. Follow the displayed job-specific bounds and format policies.