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 Swellow's top six counters needs 0.90 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 1.14 (round up: 2). The raid timer is 180 seconds and one prepared trainer alone would take 2:37. A prepared solo becomes possible at level 30. A duo works from level 20.

Swellow · Shadow Tier 3

normalflying

Weak to

rockelectricice

Boss CP: 14,913
Boss HP: 4,000
Raid timer: 180s
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	2(1.18)	2(1.31)	2(1.63)	3:51	6.0
Level 25	2(1.00)	2(1.13)	2(1.43)	3:18	5.9
Level 30	1(0.89)	1(0.98)	2(1.27)	2:51	5.4
Level 35	1(0.88)	1(0.94)	2(1.18)	2:45	4.9
Level 40	1(0.81)	1(0.90)	2(1.14)	2:37	4.6
Level 45	1(0.78)	1(0.87)	2(1.08)	2:33	4.3
Level 50	1(0.74)	1(0.83)	2(1.06)	2:25	3.8

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

Kyurem (White)0.81

A prepared party

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

1 trainer at level 40

Kyurem (White)0.81
Regieleki0.88
Zeraora0.91
Kyurem (Black)0.92
Thundurus (Therian)0.92
Xurkitree0.93

A mixed local group

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

2 trainers at level 40

Gigalith1.08
Glimmora1.07
Zacian (Crowned Sword)1.08
Magnezone1.12
Rhyperior1.12
Necrozma (Dusk Mane)1.15

The party these numbers assume

1. Kyurem (White)

Ice Fang + Ice Burn

2. Regieleki

Thunder Shock + Thunder Cage

3. Zeraora

Volt Switch + Plasma Fists

4. Kyurem (Black)

Dragon Tail + Freeze Shock

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.