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 3 to be safe — 2 if everyone is prepared

At level 40, a party of Mega Metagross's top six counters needs 1.83 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 2.16 (round up: 3). The raid timer is 300 seconds and one prepared trainer alone would take 8:29. No level in this range makes it soloable with a prepared party. A duo works from level 35.

Mega Metagross · Mega

steelpsychic

Weak to

groundghostfiredark

Boss CP: 52,103
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 Metagross 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	3(2.48)	3(2.80)	4(3.43)	13:02	6.0
Level 25	2(1.94)	3(2.30)	3(2.74)	10:42	6.0
Level 30	2(1.65)	3(2.06)	3(2.38)	9:34	6.0
Level 35	2(1.60)	2(1.94)	3(2.25)	9:00	6.0
Level 40	2(1.56)	2(1.83)	3(2.16)	8:29	6.0
Level 45	2(1.49)	2(1.74)	3(2.06)	8:05	6.0
Level 50	2(1.45)	2(1.65)	2(2.00)	7:41	6.0

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)1.56

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)1.56
Darkrai1.87
Landorus (Therian)1.90
Reshiram1.90
Blacephalon1.84
Lunala1.90

A mixed local group

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

3 trainers at level 40

Hoopa (Unbound)2.13
Volcarona2.10
Heatran2.08
Dragapult2.13
Kingambit2.16
Victini2.17

The party these numbers assume

1. Necrozma (Dawn Wings)

Shadow Claw + Moongeist Beam

2. Darkrai

Snarl + Foul Play

3. Landorus (Therian)

Mud Shot + Sandsear Storm

4. Reshiram

Fire Fang + Fusion Flare

5. Blacephalon

Astonish + Mind Blown

6. Lunala

Shadow Claw + Shadow Ball

See the full ranked counter list for Mega Metagross · 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.