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 2 to be safe — 2 if everyone is prepared

At level 40, a party of Gengar's top six counters needs 1.15 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 1.40 (round up: 2). The raid timer is 180 seconds and one prepared trainer alone would take 3:22. No level in this range makes it soloable with a prepared party. A duo works from level 20.

Gengar · Shadow Tier 3

ghostpoison

Weak to

groundghostpsychicdark

Boss CP: 22,354
Boss HP: 4,000
Raid timer: 180s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Gengar 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(1.37)	2(1.89)	3(2.24)	5:32	5.9
Level 25	2(1.23)	2(1.50)	2(1.83)	4:23	5.7
Level 30	2(1.13)	2(1.32)	2(1.57)	3:52	5.4
Level 35	2(1.05)	2(1.22)	2(1.48)	3:35	5.2
Level 40	2(1.01)	2(1.15)	2(1.40)	3:22	5.1
Level 45	1(0.97)	2(1.11)	2(1.35)	3:15	4.9
Level 50	1(0.96)	2(1.08)	2(1.29)	3:09	4.7

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

Necrozma (Dawn Wings)1.01

A prepared party

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

2 trainers at level 40

Necrozma (Dawn Wings)1.01
Mewtwo1.07
Landorus (Therian)1.16
Hoopa (Unbound)1.16
Necrozma (Dusk Mane)1.22
Giratina (Origin)1.28

A mixed local group

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

2 trainers at level 40

Salamence1.36
Tyranitar1.36
Latios1.36
Zacian (Crowned Sword)1.38
Hisuian Zoroark1.37
Metagross1.38

The party these numbers assume

1. Necrozma (Dawn Wings)

Psycho Cut + Moongeist Beam

2. Mewtwo

Psycho Cut + Psystrike

3. Landorus (Therian)

Mud Shot + Sandsear Storm

4. Hoopa (Unbound)

Confusion + Psychic

5. Necrozma (Dusk Mane)

Psycho Cut + Sunsteel Strike

6. Giratina (Origin)

Shadow Claw + Shadow Force

See the full ranked counter list for Gengar · 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.