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 1 to be safe — 1 if everyone is prepared

At level 40, a party of Gourgeist (Average)'s top six counters needs 0.68 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 0.85 (round up: 1). The raid timer is 180 seconds and one prepared trainer alone would take 2:00. A prepared solo becomes possible at level 25. A duo works from level 20.

Gourgeist (Average) · Tier 3

ghostgrass

Weak to

flyingghostfireicedark

Boss CP: 17,213
Boss HP: 3,600
Raid timer: 180s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Gourgeist (Average) 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	2(1.12)	2(1.03)	2(1.23)	3:01	5.3
Level 25	2(1.02)	1(0.88)	2(1.05)	2:35	4.5
Level 30	1(0.74)	1(0.77)	1(0.94)	2:15	3.8
Level 35	1(0.69)	1(0.72)	1(0.89)	2:07	3.4
Level 40	1(0.65)	1(0.68)	1(0.85)	2:00	3.0
Level 45	1(0.62)	1(0.67)	1(0.81)	1:57	2.9
Level 50	1(0.63)	1(0.64)	1(0.79)	1:53	2.6

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.

1 trainer at level 40

Necrozma (Dawn Wings)0.65

A prepared party

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

1 trainer at level 40

Necrozma (Dawn Wings)0.65
Kyurem (White)0.65
Kyurem (Black)0.66
Rayquaza0.68
Blacephalon0.72
Reshiram0.73

A mixed local group

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

1 trainer at level 40

Galarian Articuno0.82
Hydreigon0.84
Zamazenta (Crowned Shield)0.84
Staraptor0.85
Honchkrow0.83
Heatran0.84

The party these numbers assume

1. Necrozma (Dawn Wings)

Psycho Cut + Moongeist Beam

2. Kyurem (White)

Ice Fang + Ice Burn

3. Kyurem (Black)

Shadow Claw + Freeze Shock

4. Rayquaza

Air Slash + Dragon Ascent

5. Blacephalon

Incinerate + Mind Blown

6. Reshiram

Fire Fang + Fusion Flare

See the full ranked counter list for Gourgeist (Average) · 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.