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 Swellow's top six counters needs 2.18 trainers (round up: 3), and a mixed lobby of ranks 13-24 needs 2.76 (round up: 3). The raid timer is 300 seconds and one prepared trainer alone would take 10:03. No level in this range makes it soloable with a prepared party.

Swellow · Elite

normalflying

Weak to

rockelectricice

Boss CP: 33,346
Boss HP: 20,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Swellow 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(2.90)	4(3.23)	5(4.10)	14:53	6.0
Level 25	3(2.44)	3(2.73)	4(3.46)	12:33	6.0
Level 30	3(2.17)	3(2.41)	4(3.02)	11:04	6.0
Level 35	3(2.09)	3(2.30)	3(2.88)	10:35	6.0
Level 40	2(1.98)	3(2.18)	3(2.76)	10:03	6.0
Level 45	2(1.89)	3(2.09)	3(2.65)	9:37	6.0
Level 50	2(1.82)	3(2.01)	3(2.54)	9:15	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)1.98

A prepared party

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

3 trainers at level 40

Kyurem (White)1.98
Regieleki2.10
Kyurem (Black)2.19
Zeraora2.24
Thundurus (Therian)2.28
Xurkitree2.30

A mixed local group

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

3 trainers at level 40

Zacian (Crowned Sword)2.64
Raikou2.66
Electivire2.67
Rhyperior2.69
Gigalith2.71
Magnezone2.72

The party these numbers assume

1. Kyurem (White)

Ice Fang + Ice Burn

2. Regieleki

Lock-On + Thunder Cage

3. Kyurem (Black)

Dragon Tail + Freeze Shock

4. Zeraora

Volt Switch + Plasma Fists

5. Thundurus (Therian)

Volt Switch + Wildbolt Storm

6. Xurkitree

Thunder Shock + Discharge

See the full ranked counter list for Swellow · 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.