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 5 to be safe — 5 if everyone is prepared

At level 40, a party of Arceus (Grass)'s top six counters needs 4.10 trainers (round up: 5), and a mixed lobby of ranks 13-24 needs 4.77 (round up: 5). The raid timer is 300 seconds and one prepared trainer alone would take 18:53. No level in this range makes it soloable with a prepared party.

Arceus (Grass) · Elite

grass

Weak to

flyingpoisonbugfireice

Boss CP: 56,910
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 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	8(7.00)	9(8.14)	9(8.31)	37:28	6.0
Level 25	5(4.70)	6(5.66)	7(6.69)	26:04	6.0
Level 30	5(4.16)	5(4.63)	6(5.39)	21:18	6.0
Level 35	4(3.92)	5(4.25)	6(5.09)	19:33	6.0
Level 40	4(3.75)	5(4.10)	5(4.77)	18:53	6.0
Level 45	4(3.60)	4(3.97)	5(4.67)	18:15	6.0
Level 50	4(3.48)	4(3.76)	5(4.51)	17:18	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.

4 trainers at level 40

Kyurem (White)3.75

A prepared party

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

5 trainers at level 40

Kyurem (White)3.75
Rayquaza3.92
Eternatus4.16
Kyurem (Black)4.20
Salamence4.22
Reshiram4.38

A mixed local group

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

5 trainers at level 40

Heatran4.56
Zamazenta (Crowned Shield)4.56
Necrozma (Dusk Mane)4.73
Cinderace4.72
Zacian (Crowned Sword)4.78
Vikavolt4.74

The party these numbers assume

1. Kyurem (White)

Ice Fang + Ice Burn

2. Rayquaza

Air Slash + Dragon Ascent

3. Eternatus

Poison Jab + Dynamax Cannon

4. Kyurem (Black)

Dragon Tail + Freeze Shock

5. Salamence

Fire Fang + Fly

6. Reshiram

Fire Fang + Fusion Flare

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.