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 Mega Victreebel's top six counters needs 1.05 trainers (round up: 2), and a mixed lobby of ranks 13-24 needs 1.27 (round up: 2). The raid timer is 300 seconds and one prepared trainer alone would take 4:52. A prepared solo becomes possible at level 45. A duo works from level 20.

Mega Victreebel · Mega

grasspoison

Weak to

flyingfirepsychicice

Boss CP: 37,188
Boss HP: 9,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Mega Victreebel 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(1.42)	2(1.57)	2(1.88)	7:18	6.0
Level 25	2(1.22)	2(1.35)	2(1.62)	6:16	5.9
Level 30	2(1.06)	2(1.16)	2(1.41)	5:25	5.8
Level 35	2(1.01)	2(1.11)	2(1.34)	5:09	5.7
Level 40	1(0.97)	2(1.05)	2(1.27)	4:52	5.6
Level 45	1(0.94)	1(1.00)	2(1.23)	4:38	5.4
Level 50	1(0.89)	1(0.96)	2(1.18)	4:29	5.3

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)0.97

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)0.97
Rayquaza0.99
Mewtwo1.05
Blacephalon1.06
Kyurem (Black)1.10
Reshiram1.11

A mixed local group

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

2 trainers at level 40

Necrozma (Dawn Wings)1.24
Enamorus (Incarnate)1.26
Heatran1.25
Zacian (Crowned Sword)1.26
Eternatus1.26
Zamazenta (Crowned Shield)1.27

The party these numbers assume

1. Kyurem (White)

Ice Fang + Ice Burn

2. Rayquaza

Air Slash + Dragon Ascent

3. Mewtwo

Psycho Cut + Psystrike

4. Blacephalon

Incinerate + Mind Blown

5. Kyurem (Black)

Dragon Tail + Freeze Shock

6. Reshiram

Fire Fang + Fusion Flare

See the full ranked counter list for Mega Victreebel · 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.