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 (Fighting)'s top six counters needs 2.42 trainers (round up: 3), and a mixed lobby of ranks 13-24 needs 2.89 (round up: 3). The raid timer is 300 seconds and one prepared trainer alone would take 11:09. No level in this range makes it soloable with a prepared party.

Arceus (Fighting) · Tier 5

fighting

Weak to

flyingpsychicfairy

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 (Fighting) 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(4.42)	4(3.87)	5(4.55)	17:49	6.0
Level 25	3(2.98)	4(3.04)	4(3.66)	14:00	6.0
Level 30	3(2.51)	3(2.67)	4(3.18)	12:17	5.9
Level 35	3(2.38)	3(2.55)	4(3.03)	11:44	5.9
Level 40	3(2.30)	3(2.42)	3(2.89)	11:09	5.9
Level 45	3(2.22)	3(2.34)	3(2.77)	10:46	5.9
Level 50	3(2.17)	3(2.25)	3(2.66)	10:21	5.8

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

Rayquaza2.30

A prepared party

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

3 trainers at level 40

Rayquaza2.30
Mewtwo2.33
Enamorus (Incarnate)2.40
Hoopa (Unbound)2.45
Zacian (Crowned Sword)2.51
Galarian Articuno2.54

A mixed local group

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

3 trainers at level 40

Lunala2.75
Salamence2.78
Toucannon2.78
Lugia2.87
Braviary2.89
Hoopa2.89

The party these numbers assume

1. Rayquaza

Air Slash + Dragon Ascent

2. Mewtwo

Psycho Cut + Psystrike

3. Enamorus (Incarnate)

Fairy Wind + Fly

4. Hoopa (Unbound)

Confusion + Psychic

5. Zacian (Crowned Sword)

Air Slash + Play Rough

6. Galarian Articuno

Psycho Cut + Fly

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