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 6 to be safe — 5 if everyone is prepared

At level 40, a party of Cresselia's top six counters needs 4.58 trainers (round up: 5), and a mixed lobby of ranks 13-24 needs 5.28 (round up: 6). The raid timer is 300 seconds and one prepared trainer alone would take 21:05. No level in this range makes it soloable with a prepared party.

Cresselia · Elite

psychic

Weak to

bugghostdark

Boss CP: 39,022
Boss HP: 20,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Cresselia 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	6(5.50)	7(6.77)	8(7.53)	31:09	6.0
Level 25	5(4.48)	6(5.81)	7(6.64)	26:44	6.0
Level 30	5(4.01)	6(5.19)	6(5.90)	23:54	5.9
Level 35	4(3.80)	5(4.98)	6(5.66)	22:55	5.9
Level 40	4(3.69)	5(4.58)	6(5.28)	21:05	5.8
Level 45	4(3.56)	5(4.46)	6(5.15)	20:32	5.8
Level 50	4(3.41)	5(4.36)	5(4.97)	20:04	5.7

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.

4 trainers at level 40

Necrozma (Dawn Wings)3.69

A prepared party

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

5 trainers at level 40

Necrozma (Dawn Wings)3.69
Blacephalon4.59
Darkrai4.67
Lunala4.79
Necrozma (Dusk Mane)4.81
Giratina (Origin)4.93

A mixed local group

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

6 trainers at level 40

Zacian (Crowned Sword)5.13
Dragapult5.19
Hoopa5.25
Incineroar5.28
Weavile5.32
Kartana5.31

The party these numbers assume

1. Necrozma (Dawn Wings)

Psycho Cut + Moongeist Beam

2. Blacephalon

Astonish + Shadow Ball

3. Darkrai

Snarl + Foul Play

4. Lunala

Shadow Claw + Shadow Ball

5. Necrozma (Dusk Mane)

Shadow Claw + Sunsteel Strike

6. Giratina (Origin)

Shadow Claw + Shadow Force

See the full ranked counter list for Cresselia · 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.