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 Haunter's top six counters needs 0.40 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 0.48 (round up: 1). The raid timer is 180 seconds and one prepared trainer alone would take 1:10. A prepared solo becomes possible at level 20. A duo works from level 20.

Haunter · Tier 3

ghostpoison

Weak to

groundghostpsychicdark

Boss CP: 15,772
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 Haunter 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	1(0.61)	1(0.61)	1(0.73)	1:46	4.7
Level 25	1(0.44)	1(0.50)	1(0.62)	1:28	3.5
Level 30	1(0.38)	1(0.45)	1(0.53)	1:19	2.5
Level 35	1(0.36)	1(0.42)	1(0.51)	1:14	2.1
Level 40	1(0.33)	1(0.40)	1(0.48)	1:10	1.8
Level 45	1(0.32)	1(0.38)	1(0.47)	1:08	1.6
Level 50	1(0.32)	1(0.38)	1(0.45)	1:06	1.5

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)0.33

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)0.33
Mewtwo0.38
Hoopa (Unbound)0.40
Landorus (Therian)0.41
Darkrai0.43
Groudon0.45

A mixed local group

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

1 trainer at level 40

Tyranitar0.47
Hisuian Zoroark0.47
Eternatus0.47
Chandelure0.48
Excadrill0.48
Dragapult0.48

The party these numbers assume

1. Necrozma (Dawn Wings)

Psycho Cut + Moongeist Beam

2. Mewtwo

Confusion + Psystrike

3. Hoopa (Unbound)

Confusion + Psychic

4. Landorus (Therian)

Extrasensory + Sandsear Storm

5. Darkrai

Snarl + Foul Play

6. Groudon

Mud Shot + Precipice Blades

See the full ranked counter list for Haunter · 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.