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THE FEUTEX TOOLKIT

Independent Drop Confidence

Estimate the chance of at least one drop and runs needed to reach a confidence target.

Game Design workspace● Runs in your browser
01 Your input
02 Your result
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FormulaChance of at least one drop = 100*(1-(1-p/100)**n); Runs for confidence target = ceil(log(1-confidence/100)/log(1-p/100))

Worked example

Inputs

Drop chance per run
10 %
Planned runs
10 runs
Target confidence
95 %

Expected results

Chance of at least one drop
65.13215599 %
Runs for confidence target
29 runs

Load the example in the workspace to reproduce these results. Display rounding does not change the underlying calculation.

How to use this tool

  1. Estimate the chance of at least one drop and runs needed to reach a confidence target.
  2. Set drop chance per run, planned runs, target confidence in the indicated units.
  3. Calculate and compare chance of at least one drop, runs for confidence target.

Try this example

{
  "p": 10,
  "n": 10,
  "confidence": 95
}

Accuracy and scope

Independent attempts with an unchanged probability; excludes pity systems and dependent loot tables. User-defined game-rule arithmetic; no current game mechanics or search-volume claims.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.