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 4 to be safe — 3 if everyone is prepared

At level 40, a party of Arceus (Fire)'s top six counters needs 2.76 trainers (round up: 3), and a mixed lobby of ranks 13-24 needs 3.12 (round up: 4). The raid timer is 300 seconds and one prepared trainer alone would take 12:43. No level in this range makes it soloable with a prepared party.

Arceus (Fire) · Tier 5

fire

Weak to

groundrockwater

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 (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	5(4.20)	5(4.44)	5(4.74)	20:25	6.0
Level 25	4(3.35)	4(3.61)	4(3.93)	16:35	6.0
Level 30	3(2.84)	4(3.08)	4(3.49)	14:09	6.0
Level 35	3(2.77)	3(2.91)	4(3.28)	13:24	6.0
Level 40	3(2.62)	3(2.76)	4(3.12)	12:43	6.0
Level 45	3(2.52)	3(2.67)	4(3.03)	12:18	6.0
Level 50	3(2.50)	3(2.61)	3(2.91)	12:00	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

Landorus (Therian)2.62

A prepared party

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

3 trainers at level 40

Landorus (Therian)2.62
Inteleon2.65
Groudon2.77
Kyogre2.77
Rampardos2.86
Primarina2.92

A mixed local group

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

4 trainers at level 40

Necrozma (Dawn Wings)2.97
Kingler3.02
Swampert3.10
Garchomp3.12
Empoleon3.10
Gigalith3.14

The party these numbers assume

1. Landorus (Therian)

Mud Shot + Sandsear Storm

2. Inteleon

Water Gun + Hydro Cannon

3. Groudon

Mud Shot + Precipice Blades

4. Kyogre

Waterfall + Origin Pulse

5. Rampardos

Smack Down + Rock Slide

6. Primarina

Waterfall + Hydro Cannon

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.