How it works
Independent attempts with constant success probability have expected attempts to first success of 1/p, multiplied by a constant attempt duration. This form solves for duration per attempt; enter the known quantities in Expected time to first success, Success probability per attempt.
Inputs and units
| Input | Example value | What to enter |
|---|---|---|
| Expected time to first success | 10 min | Formula symbol: time. Required unit: min. Must be greater than zero. |
| Success probability per attempt | 20 % | Formula symbol: p. Enter the percentage as a number: for 15%, enter 15. Must be greater than zero. Allowed range: 0.000001–100. |
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.
- Expected time to first success
- 10 min
- Success probability per attempt
- 20 %
Complete example results
- Duration per attempt
- 2 min
Reading the result
The result solves for duration per attempt 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 duration per attempt result?
This is a mean, not a maximum or guaranteed duration. Attempts are independent, durations constant and success probability positive; include intervening waits in the duration yourself.
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