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 Yamask's top six counters needs 1.56 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 1.79 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 7:09. No level in this range makes it soloable with a prepared party. A duo works from level 25.

Yamask · Tier 5

ghost

Weak to

ghostdark

Boss CP: 16,826
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 Yamask 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(1.88)	3(2.23)	3(2.51)	10:15	5.8
Level 25	2(1.63)	2(1.93)	3(2.17)	8:53	5.6
Level 30	2(1.44)	2(1.71)	2(1.96)	7:53	5.2
Level 35	2(1.32)	2(1.64)	2(1.87)	7:34	5.1
Level 40	2(1.24)	2(1.56)	2(1.79)	7:09	4.9
Level 45	2(1.23)	2(1.53)	2(1.72)	7:02	4.7
Level 50	2(1.18)	2(1.47)	2(1.66)	6:47	4.6

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)1.24

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)1.24
Darkrai1.53
Blacephalon1.60
Kyurem (Black)1.63
Hydreigon1.65
Absol1.68

A mixed local group

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

2 trainers at level 40

Tyranitar1.73
Gholdengo1.76
Zamazenta (Crowned Shield)1.77
Necrozma (Dusk Mane)1.76
Weavile1.78
Kingambit1.78

The party these numbers assume

1. Necrozma (Dawn Wings)

Psycho Cut + Moongeist Beam

2. Darkrai

Snarl + Foul Play

3. Blacephalon

Astonish + Shadow Ball

4. Kyurem (Black)

Shadow Claw + Freeze Shock

5. Hydreigon

Bite + Brutal Swing

6. Absol

Snarl + Brutal Swing

See the full ranked counter list for Yamask · 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.