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 1 to be safe — 1 if everyone is prepared

At level 40, a party of Grubbin's top six counters needs 0.32 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 0.37 (round up: 1). The raid timer is 180 seconds and one prepared trainer alone would take 0:56. A prepared solo becomes possible at level 20. A duo works from level 20.

Grubbin · Tier 3

bug

Weak to

flyingrockfire

Boss CP: 7,800
Boss HP: 3,600
Raid timer: 180s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Grubbin 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	1(0.37)	1(0.43)	1(0.51)	1:16	1.1
Level 25	1(0.32)	1(0.39)	1(0.45)	1:08	0.6
Level 30	1(0.30)	1(0.35)	1(0.41)	1:01	0.2
Level 35	1(0.29)	1(0.33)	1(0.39)	0:59	0.2
Level 40	1(0.27)	1(0.32)	1(0.37)	0:56	0.1
Level 45	1(0.26)	1(0.31)	1(0.36)	0:55	0.1
Level 50	1(0.26)	1(0.30)	1(0.35)	0:53	0.1

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.

1 trainer at level 40

Blacephalon0.27

A prepared party

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

1 trainer at level 40

Blacephalon0.27
Rayquaza0.29
Reshiram0.32
Salamence0.34
Enamorus (Incarnate)0.35
Chandelure0.35

A mixed local group

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

1 trainer at level 40

Zacian (Crowned Sword)0.36
Tornadus (Therian)0.36
Rampardos0.36
Heatran0.37
Staraptor0.37
Eternatus0.37

The party these numbers assume

1. Blacephalon

Incinerate + Mind Blown

2. Rayquaza

Air Slash + Dragon Ascent

3. Reshiram

Fire Fang + Fusion Flare

4. Salamence

Fire Fang + Fly

5. Enamorus (Incarnate)

Fairy Wind + Fly

6. Chandelure

Fire Spin + Overheat

See the full ranked counter list for Grubbin · 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.