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 — 2 if everyone is prepared

At level 40, a party of Tornadus (Incarnate)'s top six counters needs 1.74 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 2.20 (round up: 3). The raid timer is 300 seconds and one prepared trainer alone would take 8:01. No level in this range makes it soloable with a prepared party. A duo works from level 30.

Tornadus (Incarnate) · Tier 5

flying

Weak to

rockelectricice

Boss CP: 46,044
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 Tornadus (Incarnate) 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	3(2.28)	3(2.74)	4(3.42)	12:36	6.0
Level 25	2(1.90)	3(2.29)	3(2.89)	10:33	6.0
Level 30	2(1.69)	2(1.96)	3(2.43)	9:02	6.0
Level 35	2(1.60)	2(1.84)	3(2.30)	8:28	6.0
Level 40	2(1.54)	2(1.74)	3(2.20)	8:01	6.0
Level 45	2(1.47)	2(1.67)	3(2.09)	7:41	6.0
Level 50	2(1.41)	2(1.61)	3(2.01)	7:25	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

Kyurem (White)1.54

A prepared party

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

2 trainers at level 40

Kyurem (White)1.54
Kyurem (Black)1.72
Thundurus (Therian)1.77
Zeraora1.78
Xurkitree1.82
Regieleki1.81

A mixed local group

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

3 trainers at level 40

Electivire2.11
Zacian (Crowned Sword)2.15
Rhyperior2.16
Baxcalibur2.16
Necrozma (Dusk Mane)2.17
Magnezone2.20

The party these numbers assume

1. Kyurem (White)

Ice Fang + Ice Burn

2. Kyurem (Black)

Dragon Tail + Freeze Shock

3. Thundurus (Therian)

Volt Switch + Wildbolt Storm

4. Zeraora

Volt Switch + Plasma Fists

5. Xurkitree

Thunder Shock + Discharge

6. Regieleki

Lock-On + Thunder Cage

See the full ranked counter list for Tornadus (Incarnate) · 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.