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 Vivillon's top six counters needs 0.86 trainers (round up: 1), and a mixed lobby of ranks 13-24 needs 1.06 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 3:58. A prepared solo becomes possible at level 30. A duo works from level 20.

Vivillon · Tier 5

bugflying

Weak to

rockflyingfireelectricice

Boss CP: 25,410
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 Vivillon 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(1.14)	2(1.25)	2(1.54)	5:45	6.0
Level 25	1(0.98)	2(1.05)	2(1.32)	4:51	6.0
Level 30	1(0.89)	1(0.94)	2(1.17)	4:19	5.8
Level 35	1(0.84)	1(0.91)	2(1.11)	4:11	5.7
Level 40	1(0.80)	1(0.86)	2(1.06)	3:58	5.4
Level 45	1(0.78)	1(0.82)	2(1.03)	3:47	5.2
Level 50	1(0.75)	1(0.80)	1(0.99)	3:41	5.0

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

Glimmora0.80

A prepared party

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

1 trainer at level 40

Glimmora0.80
Rampardos0.82
Rhyperior0.87
Gigalith0.89
Terrakion0.89
Tyrantrum0.90

A mixed local group

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

2 trainers at level 40

Rayquaza1.02
Archeops1.03
Aerodactyl1.03
Lycanroc (Dusk)1.02
Landorus (Incarnate)1.04
Lycanroc (Midday)1.04

The party these numbers assume

1. Glimmora

Rock Throw + Meteor Beam

2. Rampardos

Smack Down + Rock Slide

3. Rhyperior

Smack Down + Rock Wrecker

4. Gigalith

Lock-On + Meteor Beam

5. Terrakion

Smack Down + Rock Slide

6. Tyrantrum

Rock Throw + Meteor Beam

See the full ranked counter list for Vivillon · 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.