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 — 2 if everyone is prepared

At level 40, a party of Vivillon's top six counters needs 1.45 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 1.80 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 6:41. No level in this range makes it soloable with a prepared party. A duo works from level 25.

Vivillon · Elite

bugflying

Weak to

rockflyingfireelectricice

Boss CP: 29,341
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 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	3(2.30)	3(2.18)	3(2.69)	10:01	6.0
Level 25	2(1.81)	2(1.84)	3(2.31)	8:28	6.0
Level 30	2(1.51)	2(1.60)	3(2.01)	7:23	6.0
Level 35	2(1.44)	2(1.54)	2(1.90)	7:04	6.0
Level 40	2(1.37)	2(1.45)	2(1.80)	6:41	6.0
Level 45	2(1.30)	2(1.39)	2(1.74)	6:25	5.9
Level 50	2(1.26)	2(1.35)	2(1.68)	6:12	5.9

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

Rampardos1.37

A prepared party

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

2 trainers at level 40

Rampardos1.37
Glimmora1.37
Rhyperior1.47
Tyrantrum1.49
Terrakion1.51
Gigalith1.52

A mixed local group

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

2 trainers at level 40

Rayquaza1.74
Archeops1.75
Landorus (Incarnate)1.75
Lycanroc (Dusk)1.77
Lycanroc (Midday)1.78
Blacephalon1.76

The party these numbers assume

1. Rampardos

Smack Down + Rock Slide

2. Glimmora

Rock Throw + Meteor Beam

3. Rhyperior

Smack Down + Rock Wrecker

4. Tyrantrum

Rock Throw + Meteor Beam

5. Terrakion

Smack Down + Rock Slide

6. Gigalith

Lock-On + 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.