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 Mega Raichu X's top six counters needs 1.43 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 1.86 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 6:39. No level in this range makes it soloable with a prepared party. A duo works from level 25.

Mega Raichu X · Mega

electric

Weak to

ground

Boss CP: 40,900
Boss HP: 9,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Mega Raichu 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	2(1.83)	3(2.06)	3(2.73)	9:34	5.9
Level 25	2(1.58)	2(1.77)	3(2.31)	8:13	5.9
Level 30	2(1.46)	2(1.62)	3(2.06)	7:31	5.7
Level 35	2(1.30)	2(1.50)	2(1.95)	6:58	5.6
Level 40	2(1.26)	2(1.43)	2(1.86)	6:39	5.5
Level 45	2(1.23)	2(1.37)	2(1.80)	6:22	5.4
Level 50	2(1.20)	2(1.32)	2(1.72)	6:08	5.4

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

Landorus (Therian)1.26

A prepared party

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

2 trainers at level 40

Landorus (Therian)1.26
Groudon1.36
Eternatus1.42
Necrozma (Dawn Wings)1.49
Excadrill1.53
Garchomp1.52

A mixed local group

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

2 trainers at level 40

Krookodile1.81
Keldeo1.78
Golurk1.81
Mudsdale1.85
Mewtwo1.87
Donphan1.87

The party these numbers assume

1. Landorus (Therian)

Mud Shot + Sandsear Storm

2. Groudon

Mud Shot + Precipice Blades

3. Eternatus

Poison Jab + Dynamax Cannon

4. Necrozma (Dawn Wings)

Psycho Cut + Moongeist Beam

5. Excadrill

Mud-Slap + Scorching Sands

6. Garchomp

Mud Shot + Earth Power

See the full ranked counter list for Mega Raichu 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.