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TCG Booster Pack Drop-Rate Calculator

免费集换式卡牌游戏抽卡率计算器。

何时使用

Use when designing pack composition for your indie TCG. Players will reverse-engineer the math; better to know your own odds first.

与其他指标对比

Math is the same as Magic's "to pull a mythic" calculators. This tool generalizes to any rarity structure.

Enter your values below. Calculations run locally as you type.

工作原理

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.

常见问题

Does this assume independent packs?

Yes. It uses the geometric distribution. If your set uses guaranteed rare slots (no duplicates within a pack), the real odds are slightly different.

Is 95% the right confidence target?

95% is a common design target — most players will hit the pull within that range. 50% is the "median" experience.

Why do I need far more than the average packs to hit a specific card?

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.

Does pulling one rare make the next pack more likely to contain another?

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.

示例

输入

30 rares in set, 1 rare per pack, target 1 specific copy.

输出

~88 packs for 95% confidence.

P(specific) = 1/30 ≈ 3.33%. n = log(0.05) / log(0.9667) ≈ 88.

常见陷阱

  • Real games often guarantee no duplicates within a pack — odds shift slightly.
  • Premium pull pity systems (after N packs you're guaranteed) change the distribution.
  • Don't set 95% confidence above ~200 packs — it triggers gambling-mechanic backlash.

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