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 — 3 if everyone is prepared

At level 40, a party of Celesteela's top six counters needs 2.02 trainers (round up: 3), and a mixed lobby of ranks 13-24 needs 2.49 (round up: 3). The raid timer is 300 seconds and one prepared trainer alone would take 9:17. No level in this range makes it soloable with a prepared party. A duo works from level 45.

Celesteela · Tier 5

steelflying

Weak to

fireelectric

Boss CP: 39,774
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 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	4(3.41)	4(3.17)	4(3.67)	14:35	6.0
Level 25	3(2.77)	3(2.56)	4(3.06)	11:47	6.0
Level 30	3(2.13)	3(2.25)	3(2.76)	10:20	6.0
Level 35	2(2.00)	3(2.12)	3(2.62)	9:44	6.0
Level 40	2(1.90)	3(2.02)	3(2.49)	9:17	6.0
Level 45	2(1.81)	2(1.95)	3(2.40)	8:58	6.0
Level 50	2(1.75)	2(1.87)	3(2.30)	8:36	6.0

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.

2 trainers at level 40

Blacephalon1.90

A prepared party

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

3 trainers at level 40

Blacephalon1.90
Thundurus (Therian)2.01
Regieleki2.02
Reshiram2.04
Zeraora2.05
Xurkitree2.07

A mixed local group

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

3 trainers at level 40

Raikou2.43
Ho-Oh2.43
Chandelure2.46
Blaziken2.44
Delphox2.45
Electivire2.46

The party these numbers assume

1. Blacephalon

Incinerate + Mind Blown

2. Thundurus (Therian)

Volt Switch + Wildbolt Storm

3. Regieleki

Thunder Shock + Thunder Cage

4. Reshiram

Fire Fang + Fusion Flare

5. Zeraora

Volt Switch + 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.