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 Kyurem (Black)'s top six counters needs 1.57 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 2.21 (round up: 3). The raid timer is 300 seconds and one prepared trainer alone would take 7:14. No level in this range makes it soloable with a prepared party. A duo works from level 30.

Kyurem (Black) · Tier 5

dragonice

Weak to

fightingrocksteeldragonfairy

Boss CP: 56,009
Boss HP: 15,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Kyurem (Black) 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(2.32)	3(2.46)	4(3.48)	11:19	6.0
Level 25	2(1.83)	3(2.02)	3(2.98)	9:19	6.0
Level 30	2(1.63)	2(1.78)	3(2.54)	8:12	6.0
Level 35	2(1.54)	2(1.68)	3(2.38)	7:44	6.0
Level 40	2(1.45)	2(1.57)	3(2.21)	7:14	5.9
Level 45	2(1.41)	2(1.53)	3(2.13)	7:02	5.9
Level 50	2(1.36)	2(1.45)	3(2.05)	6:39	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.

2 trainers at level 40

Zacian (Crowned Sword)1.45

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)1.45
Zamazenta (Crowned Shield)1.47
Eternatus1.50
Necrozma (Dusk Mane)1.52
Keldeo1.72
Dialga (Origin)1.77

A mixed local group

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

3 trainers at level 40

Blaziken2.08
Tinkaton2.14
Dialga2.14
Garchomp2.21
Kartana2.22
Rayquaza2.19

The party these numbers assume

1. Zacian (Crowned Sword)

Metal Claw + Behemoth Blade

2. Zamazenta (Crowned Shield)

Metal Claw + Behemoth Bash

3. Eternatus

Dragon Tail + Dynamax Cannon

4. Necrozma (Dusk Mane)

Metal Claw + Sunsteel Strike

5. Keldeo

Low Kick + Secret Sword

6. Dialga (Origin)

Metal Claw + Roar of Time

See the full ranked counter list for Kyurem (Black) · 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.