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 Arceus (Fire)'s top six counters needs 4.73 trainers (round up: 5), and a mixed lobby of ranks 13-24 needs 5.37 (round up: 6). The raid timer is 300 seconds and one prepared trainer alone would take 21:46. No level in this range makes it soloable with a prepared party.

Arceus (Fire) · Elite

fire

Weak to

groundrockwater

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 (Fire) 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	9(8.84)	8(7.89)	10(9.12)	36:18	6.0
Level 25	7(6.09)	7(6.38)	8(7.25)	29:23	6.0
Level 30	5(4.95)	6(5.35)	6(5.99)	24:37	6.0
Level 35	5(4.67)	6(5.06)	6(5.65)	23:18	6.0
Level 40	5(4.54)	5(4.73)	6(5.37)	21:46	6.0
Level 45	5(4.41)	5(4.63)	6(5.15)	21:18	6.0
Level 50	5(4.25)	5(4.46)	5(4.97)	20:32	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.

5 trainers at level 40

Landorus (Therian)4.54

A prepared party

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

5 trainers at level 40

Landorus (Therian)4.54
Kyogre4.67
Groudon4.68
Rampardos4.79
Necrozma (Dawn Wings)4.82
Rhyperior4.87

A mixed local group

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

6 trainers at level 40

Garchomp5.13
Swampert5.30
Landorus (Incarnate)5.31
Kingler5.40
Hisuian Samurott5.34
Mamoswine5.37

The party these numbers assume

1. Landorus (Therian)

Mud Shot + Sandsear Storm

2. Kyogre

Waterfall + Origin Pulse

3. Groudon

Mud Shot + Precipice Blades

4. Rampardos

Smack Down + Rock Slide

5. Necrozma (Dawn Wings)

Psycho Cut + Moongeist Beam

6. Rhyperior

Smack Down + Rock Wrecker

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