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 Clefairy's top six counters needs 1.77 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 2.41 (round up: 3). The raid timer is 300 seconds and one prepared trainer alone would take 8:09. No level in this range makes it soloable with a prepared party. A duo works from level 30.

Clefairy · Elite

fairy

Weak to

poisonsteel

Boss CP: 19,134
Boss HP: 20,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Clefairy 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(1.99)	3(2.45)	4(3.34)	11:16	5.4
Level 25	2(1.71)	3(2.13)	3(2.93)	9:48	4.8
Level 30	2(1.55)	2(1.92)	3(2.64)	8:50	4.3
Level 35	2(1.50)	2(1.85)	3(2.53)	8:32	4.0
Level 40	2(1.39)	2(1.77)	3(2.41)	8:09	3.8
Level 45	2(1.38)	2(1.71)	3(2.33)	7:52	3.6
Level 50	2(1.34)	2(1.66)	3(2.27)	7:38	3.5

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.

2 trainers at level 40

Zacian (Crowned Sword)1.39

A prepared party

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

2 trainers at level 40

Zacian (Crowned Sword)1.39
Zamazenta (Crowned Shield)1.52
Necrozma (Dusk Mane)1.52
Eternatus2.02
Metagross2.05
Necrozma (Dawn Wings)2.11

A mixed local group

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

3 trainers at level 40

Genesect (Burn)2.35
Genesect (Chill)2.35
Genesect (Douse)2.35
Genesect (Shock)2.35
Roserade2.36
Dialga (Origin)2.37

The party these numbers assume

1. Zacian (Crowned Sword)

Metal Claw + Behemoth Blade

2. Zamazenta (Crowned Shield)

Metal Claw + Behemoth Bash

3. Necrozma (Dusk Mane)

Metal Claw + Sunsteel Strike

4. Eternatus

Poison Jab + Sludge Bomb

5. Metagross

Bullet Punch + Meteor Mash

6. Necrozma (Dawn Wings)

Metal Claw + Moongeist Beam

See the full ranked counter list for Clefairy · 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.