How it works
Independent trials with constant success probability have zero-success probability (1−p)^n; its complement is used. This form solves for independent trial count; enter the known quantities in Probability of at least one success, Success probability per trial.
Inputs and units
| Input | Example value | What to enter |
|---|---|---|
| Probability of at least one success | 65.13215599 % | Formula symbol: q. Enter the percentage as a number: for 15%, enter 15. Use a non-negative value. Allowed range: 0–100. |
| Success probability per trial | 10 % | Formula symbol: p. Enter the percentage as a number: for 15%, enter 15. Use a non-negative value. Allowed range: 0–100. |
Worked example
Show example inputs and results
This example is generated by the same calculation engine using the starting values in the form. Your own inputs produce your own result.
- Probability of at least one success
- 65.13215599 %
- Success probability per trial
- 10 %
Complete example results
- Independent trial count
- 10
Reading the result
The result solves for independent trial count from the entered quantities. Check the result unit and the formula conditions before using it.
Questions and answers
Can I use the example values for my own calculation?
The example values illustrate the calculation. Replace every input with your own information, especially dates, rates and the selected operation.
When can I use the independent trial count result?
Trials must be independent. A target probability does not guarantee an outcome. Required trials round up; a 100% target and singular inverse boundaries do not give a finite count.
Why are some results rounded?
Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.
Are my inputs sent to a server?
The calculator processes inputs in your browser. Its code does not send your values to a server.
Method sources: ocw.mit.edu