Raid catch IV checker

I just caught this — is it worth keeping?

A raid, research, hatch or Rocket encounter is a fixed level with a floor under every IV, so the CP the game prints narrows the spread to a handful of possibilities — and the HP usually finishes the job. Every candidate below is produced by the app's own CP and stat formulas, the same ones the counters page builds attackers with.

SpeciesWhere it came fromWeather boosted?CPHP (optional, narrows it down)

Raid catches are level 20 (25 when the boss's type is weather boosted) with every IV at least 10.

82.2%, whichever of the 2 it is

2 spreads fit and all of them are 82.2%, so the CP and the HP have already settled how good this catch is — 12/10/15 or 11/12/14, differing only in how the same total is split. The HP has already been used; only the appraisal can separate these.

Mewtwo

psychic

Base 300 attack / 182 defense / 214 stamina · caught at level 20

Spreads that fit: 2 of 216
Best possible: 82.2%
CP range at this level: 2294–2387
HP range: 133–136

Possible IV spreads

Scroll sideways for stat product and the level 40 / 50 CP.

Every IV spread Mewtwo can have at CP 2334
Attack	Defense	Stamina	IV %	Stars	HP	Stat product (L40)	CP at 40	CP at 50
12best attack	10	15	82.2%		136	6,735k	4,086	4,619
11	12	14	82.2%		136	6,783k	4,085	4,618

What to do with it

Attack is somewhere between 11 and 12. The HP has already been used, so only the in-game appraisal can separate these — assume the lowest attack until it tells you otherwise.
Powered to level 40 it would be CP 4,086 — price that power-up and see what it buys.
Check its movesets before you TM anything, and compare it with its Shadow and Mega forms.

How this is worked out

Every one of the 216 spreads this catch source allows is run through calcCp and effectiveStats in src/engine/stats.ts at level 20, and the ones whose CP (and HP, when you give it) match are listed. There is no estimation and no search heuristic — the whole space is 216 rows, so the answer is exact. Stat product is attack x defense x HP at level 40; the star bands are the in-game appraisal thresholds by IV total out of 45 — one star to 48.9%, two from 51.1%, three from 66.7%, four from 82.2%.