Your Reroll Plan
Total Rolls Available18
Success Probability16.6%
Expected Rolls (Mean)17
90% Confidence Cost (Robux)1,725 R$
Pity Threshold78 / 80
Race Reroll Probability Calculator
Translate your reroll budget into a probability, a 90% confidence cost, and a pity threshold readout.
About this tool
Drop rates are conservative estimates based on published community data (Dragoon 1/100, Angel 1/25, etc.). The 80-roll pity threshold is a working assumption; refresh this if the developer publishes an official pity system.
How the math works
Total Rolls = Owned + floor(Robux / Cost). With 2x Luck, the target rate is doubled. Success Probability uses the cumulative binomial: 1 - (1 - p)^n. The 90% Confidence Cost solves for n in 0.10 = (1 - p)^n and converts the remainder above Owned Rerolls into Robux. Pity threshold is read against a hard-coded 80-roll guarantee; if your pity counter plus total rolls crosses the threshold, the result snaps to 100%.