Free trading card game drop-rate calculator. Define set size, pack composition, and rarity tier ratios; outputs probability of pulling a specific rare per pack and the number of packs for 50% / 95% certainty.
Use when designing pack composition for your indie TCG. Players will reverse-engineer the math; better to know your own odds first.
Math is the same as Magic's "to pull a mythic" calculators. This tool generalizes to any rarity structure.
Each pack independently rolls a rare; P(specific rare) = rares per pack ÷ total rares in the set.
Number of packs needed for a given confidence: n = log(1 − P) ÷ log(1 − p). For 95% confidence, n = log(0.05) ÷ log(1 − p).
The math assumes packs are independent (Wonka golden-ticket model). Sets with anti-duplicate rules behave slightly differently.
Yes. It uses the geometric distribution. If your set uses guaranteed rare slots (no duplicates within a pack), the real odds are slightly different.
95% is a common design target — most players will hit the pull within that range. 50% is the "median" experience.
Pull rates are probabilities, not guarantees, so a 1-in-10 rare averages ten packs but individual luck varies widely. Reaching 95% certainty for a specific card can take roughly three times the average because random misses stack up.
No. Each sealed pack is randomized independently, so past pulls do not change future odds. The gambler's belief that you are due for a hit after a dry streak does not hold for booster packs.
الإدخال
30 rares in set, 1 rare per pack, target 1 specific copy.
الناتج
~88 packs for 95% confidence.
P(specific) = 1/30 ≈ 3.33%. n = log(0.05) / log(0.9667) ≈ 88.
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