Group size estimator

How many trainers do I need to invite?

The Estimator is already "trainers of this attacker needed to finish inside the timer", so this page does not invent a number: it reads it off the boss's own ranked counter list for three realistic parties and re-simulates each of them at every level from 20 to 50.

Raid bossTierIVsWeatherFriendshipDodgingShadow attackersMega attackersLegendary attackers

Invite 3 to be safe — 3 if everyone is prepared

At level 40, a party of Cosmoem's top six counters needs 2.39 trainers (round up: 3), and a mixed lobby of ranks 13-24 needs 2.81 (round up: 3). The raid timer is 300 seconds and one prepared trainer alone would take 10:59. No level in this range makes it soloable with a prepared party.

Cosmoem · Tier 5

psychic

Weak to

bugghostdark

Boss CP: 13,547
Boss HP: 15,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Cosmoem at each attacker level
Attacker level	Six of the best counter	A prepared party	A mixed local group	Prepared solo time	Faints per timer
Level 20	3(2.71)	4(3.26)	4(3.70)	15:01	2.3
Level 25	3(2.35)	3(2.83)	4(3.32)	13:02	1.8
Level 30	3(2.08)	3(2.63)	4(3.08)	12:06	1.5
Level 35	3(2.03)	3(2.55)	3(2.92)	11:44	1.3
Level 40	2(1.99)	3(2.39)	3(2.81)	10:59	1.3
Level 45	2(1.98)	3(2.35)	3(2.72)	10:48	1.2
Level 50	2(1.93)	3(2.28)	3(2.66)	10:31	1.2

Whole trainers in bold, the raw estimator in brackets — 2.04 means two trainers is right on the line and three is comfortable.

Six of the best counter

Every trainer brings six copies of the single best counter — the theoretical floor.

2 trainers at level 40

Necrozma (Dawn Wings)1.99

A prepared party

Each trainer brings the boss's top six counters, powered up and correctly TM'd.

3 trainers at level 40

Necrozma (Dawn Wings)1.99
Blacephalon2.35
Pheromosa2.41
Darkrai2.47
Gengar2.53
Kyurem (Black)2.58

A mixed local group

Ranks 13-24: reasonable but unoptimised parties, which is what a public lobby usually is.

3 trainers at level 40

Cursola2.75
Necrozma (Dusk Mane)2.77
Hoopa2.76
Polteageist2.77
Volcarona2.78
Eternatus2.80

The party these numbers assume

1. Necrozma (Dawn Wings)

Shadow Claw + Moongeist Beam

2. Blacephalon

Astonish + Shadow Ball

3. Pheromosa

Bug Bite + Bug Buzz

4. Darkrai

Snarl + Foul Play

5. Gengar

Lick + Shadow Ball

6. Kyurem (Black)

Shadow Claw + Freeze Shock

See the full ranked counter list for Cosmoem · check a real lobby (win chance, who brings what) · make a share card of the top six

How this is worked out

The boss is ranked once at level 40 with rankCached (the same memoised call /raids makes), then the three bands — rank 1, ranks 1-6, ranks 13-24 — are re-simulated at each attacker level with an 8-run Monte Carlo each. Holding the party fixed and moving only its level is deliberate: it answers "what if my party were level 20" rather than "what would a level-20 player's completely different party be", and it is about ten times cheaper than re-ranking every attacker seven times. The Estimator itself is Pokebattler's definition, time to win including rejoin time divided by the raid timer.