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 — 1 if everyone is prepared

At level 40, a party of Chewtle's top six counters needs 0.94 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 1.16 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 4:19. A prepared solo becomes possible at level 35. A duo works from level 20.

Chewtle · Tier 5

water

Weak to

grasselectric

Boss CP: 15,799
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 Chewtle 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(1.25)	2(1.32)	2(1.62)	6:04	6.0
Level 25	2(1.10)	2(1.14)	2(1.42)	5:15	5.9
Level 30	1(0.99)	2(1.03)	2(1.27)	4:44	5.4
Level 35	1(0.93)	1(0.98)	2(1.22)	4:30	5.1
Level 40	1(0.89)	1(0.94)	2(1.16)	4:19	4.8
Level 45	1(0.85)	1(0.90)	2(1.13)	4:09	4.4
Level 50	1(0.79)	1(0.87)	2(1.09)	3:59	4.0

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

Regieleki0.89

A prepared party

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

1 trainer at level 40

Regieleki0.89
Kartana0.93
Zeraora0.94
Thundurus (Therian)0.95
Xurkitree0.95
Zekrom0.97

A mixed local group

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

2 trainers at level 40

Necrozma (Dawn Wings)1.11
Kyurem (Black)1.12
Meowscarada1.12
Raikou1.14
Magnezone1.17
Decidueye1.17

The party these numbers assume

1. Regieleki

Lock-On + Thunder Cage

2. Kartana

Razor Leaf + Leaf Blade

3. Zeraora

Volt Switch + Plasma Fists

4. Thundurus (Therian)

Volt Switch + Wildbolt Storm

5. Xurkitree

Thunder Shock + Discharge

6. Zekrom

Charge Beam + Fusion Bolt

See the full ranked counter list for Chewtle · 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.