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 Celesteela's top six counters needs 0.68 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 0.84 (round up: 1). The raid timer is 180 seconds and one prepared trainer alone would take 1:59. A prepared solo becomes possible at level 25. A duo works from level 20.

Celesteela · Tier 3

steelflying

Weak to

fireelectric

Boss CP: 19,485
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 Celesteela 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(1.05)	2(1.06)	2(1.25)	3:05	6.0
Level 25	1(0.85)	1(0.87)	2(1.06)	2:32	5.5
Level 30	1(0.71)	1(0.76)	1(0.94)	2:14	4.5
Level 35	1(0.66)	1(0.72)	1(0.89)	2:06	4.0
Level 40	1(0.63)	1(0.68)	1(0.84)	1:59	3.6
Level 45	1(0.61)	1(0.66)	1(0.81)	1:55	3.2
Level 50	1(0.60)	1(0.64)	1(0.79)	1:52	3.0

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

Blacephalon0.63

A prepared party

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

1 trainer at level 40

Blacephalon0.63
Regieleki0.63
Reshiram0.69
Thundurus (Therian)0.68
Zeraora0.70
Xurkitree0.73

A mixed local group

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

1 trainer at level 40

Electivire0.82
Blaziken0.81
Ho-Oh0.82
Moltres0.82
Delphox0.83
Charizard0.84

The party these numbers assume

1. Blacephalon

Incinerate + Mind Blown

2. Regieleki

Thunder Shock + Thunder Cage

3. Reshiram

Fire Fang + Fusion Flare

4. Thundurus (Therian)

Volt Switch + Wildbolt Storm

5. Zeraora

Spark + Plasma Fists

6. Xurkitree

Thunder Shock + Discharge

See the full ranked counter list for Celesteela · 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.