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 Arceus (Grass)'s top six counters needs 2.36 trainers (round up: 3), and a mixed lobby of ranks 13-24 needs 2.88 (round up: 3). The raid timer is 300 seconds and one prepared trainer alone would take 10:50. No level in this range makes it soloable with a prepared party.

Arceus (Grass) · Tier 5

grass

Weak to

flyingpoisonbugfireice

Boss CP: 49,286
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 Arceus (Grass) 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	4(3.36)	4(3.94)	5(4.67)	18:07	6.0
Level 25	3(2.75)	4(3.08)	4(3.66)	14:10	6.0
Level 30	3(2.44)	3(2.65)	4(3.19)	12:11	6.0
Level 35	3(2.34)	3(2.50)	4(3.03)	11:29	6.0
Level 40	3(2.19)	3(2.36)	3(2.88)	10:50	6.0
Level 45	3(2.10)	3(2.27)	3(2.78)	10:26	6.0
Level 50	3(2.00)	3(2.17)	3(2.68)	9:59	6.0

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.

3 trainers at level 40

Kyurem (White)2.19

A prepared party

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

3 trainers at level 40

Kyurem (White)2.19
Blacephalon2.26
Rayquaza2.30
Eternatus2.40
Kyurem (Black)2.48
Salamence2.49

A mixed local group

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

3 trainers at level 40

Zamazenta (Crowned Shield)2.76
Toucannon2.78
Galarian Articuno2.84
Nihilego2.80
Braviary2.89
Chandelure2.87

The party these numbers assume

1. Kyurem (White)

Ice Fang + Ice Burn

2. Blacephalon

Incinerate + Mind Blown

3. Rayquaza

Air Slash + Dragon Ascent

4. Eternatus

Poison Jab + Dynamax Cannon

5. Kyurem (Black)

Dragon Tail + Freeze Shock

6. Salamence

Fire Fang + Fly

See the full ranked counter list for Arceus (Grass) · 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.