Cards
Pack odds calculator
How many packs before you actually pull the card you want? The math, without the hype.
The math
If a card appears in p of packs, the chance of seeing at least one in n packs is 1 − (1 − p)^n. That assumes independent packs, which is close enough for a hobby box but not exact for cases with collation.
Published pull rates are per pack or per box depending on the set; convert before you use this. If a maker does not publish a rate, any number you enter is a guess, and the tool says so.