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 5 to be safe — 4 if everyone is prepared

At level 40, a party of Mega Mewtwo X's top six counters needs 3.55 trainers (round up: 4), and a mixed lobby of ranks 13-24 needs 4.29 (round up: 5). The raid timer is 300 seconds and one prepared trainer alone would take 16:29. No level in this range makes it soloable with a prepared party.

Mega Mewtwo X · Primal

psychicfighting

Weak to

flyingghostfairy

Boss CP: 94,179
Boss HP: 22,500
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Mega Mewtwo X 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(4.14)	7(6.29)	8(7.48)	29:15	6.0
Level 25	4(3.61)	5(4.92)	6(5.84)	22:53	6.0
Level 30	4(3.19)	5(4.01)	5(4.92)	18:39	6.0
Level 35	3(3.00)	4(3.71)	5(4.65)	17:15	6.0
Level 40	3(2.75)	4(3.55)	5(4.29)	16:29	6.0
Level 45	3(2.61)	4(3.40)	5(4.09)	15:47	6.0
Level 50	3(2.57)	4(3.27)	4(3.93)	15:12	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.

3 trainers at level 40

Necrozma (Dawn Wings)2.75

A prepared party

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

4 trainers at level 40

Necrozma (Dawn Wings)2.75
Zacian (Crowned Sword)3.64
Yveltal3.72
Moltres3.74
Lunala3.77
Rayquaza3.65

A mixed local group

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

5 trainers at level 40

Necrozma (Dusk Mane)4.02
Mewtwo4.20
Gholdengo4.24
Hoopa4.21
Chandelure4.25
Tapu Koko4.18

The party these numbers assume

1. Necrozma (Dawn Wings)

Psycho Cut + Moongeist Beam

2. Zacian (Crowned Sword)

Air Slash + Play Rough

3. Yveltal

Gust + Oblivion Wing

4. Moltres

Wing Attack + Fly

5. Lunala

Shadow Claw + Shadow Ball

6. Rayquaza

Air Slash + Dragon Ascent

See the full ranked counter list for Mega Mewtwo X · 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.