BoxDex

Guide + calculator · secret probability

Blind box secret odds, without the wishful arithmetic

“One in 144” is a per-box probability, not a promise that box 144 contains the secret. Use the calculator for any published odds, then check whether the boxes can reasonably be treated as independent draws.

For a target with per-box probability p across n independent boxes, the chance of pulling it at least once is P = 1 − (1 − p)n.

Secret odds calculator

Chance of at least one target 15.4% 24 boxes × $15.00 = $360.00

What 1 in 144 actually means

If every box has the same independent 1/144 chance, opening 144 boxes gives about a 63.3% chance of at least one hit — not 100%. The expected number of hits is one, but an expected value is an average across many repeated experiments, not a schedule for your shelf.

BoxesChance of ≥1 secretChance of none
10.7%99.3%
128.0%92.0%
2415.4%84.6%
7239.4%60.6%
14463.3%36.7%

When this formula is the wrong model

The direct formula assumes repeated independent draws with the same probability. A sealed case may use a packing rule, a guaranteed regular assortment, or a secret that replaces one regular. Those boxes are not necessarily independent of one another. Use the manufacturer’s exact case rules when they are published; do not convert a single-box odds label into a case guarantee.

Official odds, patterns and community estimates

BoxDex keeps the number and its confidence separate:

The calculator can use any of them, but the label should travel with the result. More decimal places do not make an estimated input more authoritative.

Direct odds and full-set math are different

The equation above answers “what is my chance of this one target in n boxes?” Completing a whole set with duplicates is a different problem. The BoxDex development build simulates 1,000 collectors drawing from the series distribution and reports mean, median and p90 boxes, with secrets included or excluded. That is an estimate, not a guarantee or spending recommendation.

Worked examples on this site use the classic 1/144 format where it is stated for the series. Other products use different formats and odds. Always use the number attached to the exact product you are considering.

Use the result with the collection record

Probability describes uncertainty. Your album describes what is already true. Read the result beside the missing list and duplicate count — then make your own purchasing decision. See the collection tracking guide for a clean data structure.

The same calculation, in the app.

BoxDex’s development build supports catalog odds and custom manual input. The app is not yet publicly available.

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