A Master Ball guarantees the catch, and most players only ever get one or two, ever. This tool gives a starting-point verdict based on how genuinely rare and hard-to-replace a Pokémon is - it's a heuristic, not an official probability, so treat it as a second opinion, not the final word.

Base rarity tiers

Every verdict starts from the species itself, before any context toggle is touched:

"Legendary" and "Mythical" aren't single tiers here - a species that keeps rotating back through 5-star raids (the birds, the beasts, Lugia/Ho-Oh, Darkrai, and others) scores differently than one that's genuinely shown up once and not again, regardless of which of the two official classes it belongs to. That split is checked against actual raid history, not assumed from the species class alone - see the note on each verdict for the reasoning, and Serebii's raid archive for the source.

• YesOne-off Legendaries & Mythicals that don't come back through raids, plus Poipole (the one Ultra Beast only ever offered once) - strong candidates for a Master Ball
• Leans yesUltra Beasts, frequent-raid Mythicals/Legendaries (birds, beasts, Lugia/Ho-Oh, Darkrai, and others that keep rotating back through raids), & Incense-exclusive Legendaries (the Galarian birds - no raid at all, just a recurring event window) - genuinely hard to get another, or not quite as hard as a one-off Legendary
• Probably notPseudo-legendaries & regional exclusives - strong or geographically restricted, but usually catchable again with time, travel, or a trade
• NoCommon species, and Meltan (a Mythical, but you can summon more from the Mystery Box every few days) - save it for something rarer

One exception to "before any context toggle is touched": a plain Mythical (everything except the frequent-raid ones above) starts with the "Guaranteed catch" toggle below pre-checked, which overrides this tier and lands it in No instead - see why in the toggle list below. And a handful of species - Cosmoem, Naganadel, Urshifu, Melmetal, Zygarde - are never encountered at all, only evolved into (or, for Zygarde, assembled from Cells), so they get a "can't be caught directly" verdict instead of a tier.

What the 5 context toggles do

It's shiny

A small bonus. Shininess doesn't change the catch or flee odds, but it does raise what you'd lose if this one gets away - so it nudges the verdict up, just less than the toggles below that actually make losing it more likely.

Near-max CP for a raid boss

CP is visible before you catch, and raid bosses have a fixed level, so near-max CP is a reliable proxy for a near-perfect IV - something you generally can't know ahead of time in a wild or Team GO Rocket encounter.

Low catch rate, fleeing, or Shadow

Covers anything making the catch itself genuinely risky right now - a low base catch rate, a Pokémon that keeps breaking free, or a Shadow Pokémon (which really does flee more than its normal form). It adds the same amount for every species - a frequent-raid Legendary still scores below a one-off one, since it'll be back in raids whether or not this particular catch goes well.

This raid/event won't come back

An external, checkable fact about scheduling - the raid rotation is ending, it's an Elite Raid, a ticketed one-time event - not a guess about your own future luck.

Guaranteed catch (Special Research, can't flee)

Overrides every other factor. Most Mythical Special Research rewards and some ticketed-event bonus encounters can't flee and are caught on the first throw no matter what ball you use - when that's true, rarity is irrelevant, and a Master Ball buys you nothing. Pre-checked by default for plain Mythicals, since that's how nearly all of them are actually obtained - uncheck it if a specific one turns out to be raid-available instead.

What this tool doesn't know

It has no idea what's actually in front of you - your current IVs, how many Premier Balls you have left, or anything specific to your account. Community votes further down the page are other players' opinions, not part of the algorithmic score. Spot a bad verdict or have a suggestion? Email contact@worthamasterball.com. Fan-made, not affiliated with Nintendo/Niantic - Pokémon data © The Pokémon Company/Niantic.