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 — 5 if everyone is prepared

At level 40, a party of Mega Starmie's top six counters needs 4.02 trainers (round up: 5), and a mixed lobby of ranks 13-24 needs 4.68 (round up: 5). The raid timer is 300 seconds and one prepared trainer alone would take 18:30. No level in this range makes it soloable with a prepared party.

Mega Starmie · Super Mega

waterpsychic

Weak to

bugghostgrasselectricdark

Boss CP: 71,871
Boss HP: 25,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Mega Starmie 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	6(5.22)	7(6.09)	8(7.01)	28:01	6.0
Level 25	5(4.24)	6(5.06)	6(5.91)	23:18	6.0
Level 30	4(3.65)	5(4.48)	6(5.21)	20:36	6.0
Level 35	4(3.57)	5(4.23)	5(4.90)	19:28	6.0
Level 40	4(3.46)	5(4.02)	5(4.68)	18:30	5.9
Level 45	4(3.20)	4(3.88)	5(4.47)	17:50	5.9
Level 50	4(3.10)	4(3.76)	5(4.31)	17:18	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.

4 trainers at level 40

Necrozma (Dawn Wings)3.46

A prepared party

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

5 trainers at level 40

Necrozma (Dawn Wings)3.46
Kartana3.95
Zeraora4.03
Xurkitree4.10
Kyurem (Black)4.29
Zarude4.30

A mixed local group

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

5 trainers at level 40

Eternatus4.57
Tyranitar4.44
Raikou4.61
Rillaboom4.63
Gholdengo4.64
Sceptile4.72

The party these numbers assume

1. Necrozma (Dawn Wings)

Shadow Claw + Moongeist Beam

2. Kartana

Fury Cutter + Leaf Blade

3. Zeraora

Spark + Plasma Fists

4. Xurkitree

Thunder Shock + Discharge

5. Kyurem (Black)

Shadow Claw + Fusion Bolt

6. Zarude

Vine Whip + Power Whip

See the full ranked counter list for Mega Starmie · 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.