Choose a probability model and receive its decimal, percentage, and calculation steps.
Calculate with the Probability Calculator
Enter the values below. Invalid mathematical operations are explained before a result is shown.
Probability Calculator results
Parabola graph
How to use the Probability Calculator
- Choose a calculation mode when one is available.
- Enter the required values using the examples and field notes as a guide.
- Select Calculate or press Enter.
- Review the primary result, supporting values, and working.
Worked example
Three favorable outcomes among ten equally likely outcomes gives 0.3 or 30%.
Assumptions
The calculator uses real-number arithmetic unless complex square or quadratic roots are explicitly shown. Decimal displays can be rounded while calculations retain normal browser numeric precision.
Limitations
- Probabilities are entered as decimals from 0 to 1.
- Combinatorial n is limited to 170 and binomial trials to 1,000.
Frequently asked questions
Does the Probability Calculator accept decimals and negative values?
It accepts them wherever the selected operation permits. Invalid domains are identified before a result is shown.
How are decimal results rounded?
Calculations retain JavaScript numeric precision and display a readable number of significant digits. A displayed decimal may therefore be rounded.
Are entries stored?
No. The calculation runs in your browser and this page does not store the values you enter.