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 Chesnaught's top six counters needs 2.35 trainers (round up: 3), and a mixed lobby of ranks 13-24 needs 3.02 (round up: 4). The raid timer is 300 seconds and one prepared trainer alone would take 10:49. No level in this range makes it soloable with a prepared party.

Chesnaught · Elite

grassfighting

Weak to

flyingpoisonfirepsychicicefairy

Boss CP: 45,205
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 Chesnaught 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	3(2.81)	4(3.53)	5(4.50)	16:15	6.0
Level 25	3(2.45)	3(2.92)	4(3.78)	13:27	6.0
Level 30	3(2.15)	3(2.58)	4(3.35)	11:53	6.0
Level 35	3(2.04)	3(2.46)	4(3.19)	11:19	6.0
Level 40	2(1.97)	3(2.35)	4(3.02)	10:49	5.9
Level 45	2(1.90)	3(2.26)	3(2.89)	10:25	5.9
Level 50	2(1.82)	3(2.18)	3(2.78)	10:02	5.9

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.

2 trainers at level 40

Rayquaza1.97

A prepared party

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

3 trainers at level 40

Rayquaza1.97
Yveltal2.36
Moltres2.39
Enamorus (Incarnate)2.41
Toucannon2.47
Galarian Articuno2.50

A mixed local group

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

4 trainers at level 40

Hisuian Braviary2.80
Galarian Moltres2.87
Honchkrow2.87
Unfezant3.00
Flamigo3.01
Zacian (Crowned Sword)3.03

The party these numbers assume

1. Rayquaza

Air Slash + Dragon Ascent

2. Yveltal

Gust + Oblivion Wing

3. Moltres

Wing Attack + Fly

4. Enamorus (Incarnate)

Fairy Wind + Fly

5. Toucannon

Peck + Beak Blast

6. Galarian Articuno

Psycho Cut + Fly

See the full ranked counter list for Chesnaught · 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.